maybe im prejudiced by my ascension background but i do admit i was expecting to see things like: solomonic circles,speaking in dead languages, alchemy,numerology,sacred geometry, kabbalah,,strange allegorical symbols with hidden meanings hanging on the wall,inherency as above so below and many more.
is there anybook that actually describes magic theory?
Like circular wards and summoning circles? Check.
Latin. Check. If you want more, see Ancient Magic, there's a whole section on them.
They de-emphasized "potions" in ArM5 in favor of generic "charged items" Still there, just called something else. Sorta check.
Probably not quite what you're looking for, but ArM is ALL about the numbers. Can't really call this one a check, I think.
Demphasized, but there. Labs, for example can get a virtue by being set up in an auspicious shape. There's also a LOT of astrology throughout the books. I'm gonna call this one a check.
kabbalah isn't hermetic at all, so I wouldn't expect it to be in the system. Still, they gave us Hedge Magic, anyways, Check.
ALL over the place. Shape/form boni, Verditius Elder Runes, Enigma, etc. Check, double check and triple check!
No more so than White Wolf ever gave a beginners handbook on how to actually manipulate Prime. Theory is sort of, well, theoretical?
All of Kuiti Itijin, with the modification that Numerology and Geometry are part of certain Mystery Cults, and one can initiate those virtues.
A lot of what you've listed is in The Mysteries (Revised).
Seriously, numerology, geometry, astrology, and alchemy are all things that get entire chapters dedicated to them.
(Incidentally, this point has been brought up before. I can't remember who it was, but somebody a few months ago brought up making a lot of the initial Mysteries into inherent parts of Hermetic Magic, or at least things everyone could take, because he thought they made sense for everyone to have.)
ok, what about the egyptian part of hermeticism( thoth=hermes=mercury),platonic ideals, or casting spells by invoking the names of higher beings(not as suppication but rather viewing them as archons. mighty beings.. worthy of respect but not worship or(iirc it's been a long time) external manifestations of our souls.
using the attributes(even if theoretical only) of object to achieve an effect.
for instance here a description of a ritual cast by house tremere mages in ascension.
" they gathered there when the stars were right to concentrate ceoris one of them cut off his member so that the other member could bury it becoming the metaphysical root and tree of ceoris . i wasput in the mouth of the severed head of some guy who participated in the ritual but botched.
or another tremere ritual to walk in walls like spider involves eating one. thus stealing it's attribute.
anyway if i could describe hermetic theory in mage in a few words" knowledge,rational, secular(but not atheist and may vary from house to house), getting the "best of" out of other magic groups stripping them to their bare essentials and integrating them mostly devoid of superstition , a metaphorical(or not) quest to change yourself by changing the world in theory eventually apotheosis(though few to none achieve this.),high ritual,and basically finding as much truth as possible in a world based on consensus. there are more of course but i think i illustrated my point.
that andcutthroat politics 
none of this is to say that i don't like ars magica. from what ive seen so far i like most parts of it . i just find many things like a lot of the rules very..confusing
Technically, any time you use Ritual or Ceremonial magic, you are using alchemy, sacred geometry, and numerology. That's what Artes Liberales & Philosophae, in the context of magic, is about. If you're not part of the Order, the various sigils indicating House, sanctum, and the Arts can be viewed as strange and allegorical to the uninitiated.
Kaballah is in Realms of Power The Divine (Revised for corrections to the Judaism section) as it is a Jewish element.
Numerology and Geometry and Alchemy are in The Mysteries Revised edition. There's an entire cult dedicated to using the first two, who also refuse to eat beans.
Alternate dead languages can be found in The Sundered Eagle: The Theban tribunal, but most magi use Latin because it's Roman, and because most academic books are in that language anyway. The Theban tribunal uses ancient Greek as is very snobby about it.
Mystic symbology can be found in Houses of Hermes: Mystery Cults. House Verditius uses many. Other houses might have them as decorative elements, but symbology is a big thing to magi, it's just something you roleplay, not something inherent in the mechanics.
Circular wards exist in the core rules, there's a particular subgroup of House Ex Misc (Houses of Hermes: Socieatates) which specialists in wards. Solomonic Magic is part of a rival tradition to the Order, and can be found in The Cradle and the Crescent: The Mythic Middle-East. The Order of Suiliman exists.
Other rivals to the orders power exist in Rival Magic.
Hermetic magic is mostly named because it's self contained and sealed. There's none of this foolish worshiping of pagan gods and invoking their powers, your magic comes from YOU. If you're a Merinita, you can bargain with the fae, but you are aware your magic is YOURS first. A Bjonrnaer might beseech their ancestors for aid, but they are aware it's down to them to act first. There is no outside force going to aid you, indeed most of the beings that control magic are sealed away and cannot affect things (and in theory this is fortunate, given they are magic, and do not CARE about humanity, making them essentially entities from HP. Lovecraft's style of work.)
Invoking the names of higher beings? You're in luck! Theurgy is part of the Mysteries as well! And Platonic ideals aren't really the Order of Hermes' thing, they're more Aristotelean, for Platonic you'll want to look at the Learned Magicians in Hedge Magic.
And as much as members of the Order probably wish it was true, your description is inaccurate. The Order is most certainly not a united font searching for secular truth, far from it; most magi just do whatever suits them. And many are Christian, several pagans in there too.
And don't even start with me on the idea of Hermetic Magic being a science. It's semi-reliable, sure, but you have to remember, it's based on the same wacky thought process as magic was thought to require back then. Arbitrary symbolism matching to power, magic being inherent in more perfect things, ingredients that have nothing to do with one another mixing to make potent poultices, the entire mechanics of spellcasting botches and experimentation? Hermetic Magic is not scientific. It is an art, a mystical power beyond fathoming. A realization that the duck is a symbolism for life's journey will help you invent more spells than an understanding of math ever could.
... Criamon are actually pretty big fans of making things go wrong with magic and watching the fireworks, I've heard 
Don't listen to that liar from the Lyceum! Hermetic magic is entirely compatible with the world of Forms!
...seriously, pick up Art & Academe, the Philosophiae chapter is absolutely studded with debates between magi who believe in Platonic and Aristotelian magic.
Your zeal will not deter people from coming to the understanding that Plato was correct all along.
I think the game's original designers did a great job conceptualising the magic system. It's flexible and powerful and really contains everything you need to play accomplished magi. However... On the naming front, not so much.
As you alluded to, scholars of real-world Hermetic practice would recognise nothing of the fifteen Arts and the various spell guidelines, to say nothing of Houses and Tribunals.
But also, as has been mentioned in the thread already, there's a great book (by two of the very nicest people you could meet) in The Mysteries: Revised Edition. That really does delve into the secrets of astrology and alchemy and numerology. If you haven't picked that book up yet I recommend it.
One of the conceits of the game world is the division of the supernatural into four distinct realms. In real-world occult practice there wasn't such a division. For the most part (I'm no scholar), magical practice was part of an overarching occult world that encompassed both religious practice and the belief in the summoning and compelling of spirits (evil or otherwise).
So you can find all sorts of magic within the broader Ars Magica game, but you will most likely find them broken down such that the component parts are available individually through various magical/pious/infernal Traditions and/or Virtues.
Thoth gets a mention in the deep history of the Order. People know he's Hermes, but that Hermes himself doesn't matter much anymore.
The art of Creo taps into the Realm of Forms.
I think we moved away from the obsession with genitals, basically. And angst. It's more of a thematic thing than a design decision.
That'd be a flaw in the magic, kind of like the shapeshifting spells that require little pelts. Hermetic magic might, theoretically, include that as a Flaw.