Man, I seem to be making a lot of topics lately... oh well, lots of questions!
Is there anything preventing something/one into a regio with an Arcane Connection?
How about another Realm entirely?
I suspect if there are no entry barriers you are not currently overcoming (requires a guide, must have a copper coin in your left hand, for example), then it should be fine (such as the Barrier to Arcadia), but I have no idea.
As the rules stand, there is nothing stopping you from teleporting across a regio boundary, the issue isn't addressed at all.
IMS however we house ruled that you can't teleport across the boundary. This makes certain areas much harder to get to (allowing for more fun plot hooks to occur) and also makes regios desireable defensive locations. IMS for instance, blackthorn is located in a large regio in the Yorkshire Moors. Access is allowed only by those who know the regios entry points (and these are few and far between) or via a hermes portal in a tavern in York (heavily guarded).
Our troupe treats teleporting as an option to be taken into account. I admit it makes live harder for the ST, but it also opens up other possibilities. It often gets my character stuck somewhere without shield grogs to rely on for instance.
The bigger problem for us is the flavour of the game: when you can just teleport to any covenant you know, you lose much of the 'flair of medieval travel.'
Teleporting accros regio boundaries is possible and sometime needed. This has fueled the creation of teleporting spells by our magi, thus creating a story in its own. (and we're now trying to get a 'mass teleport' lab text from somewhere, since those grogs really need to come along to most places that require teleporting)
In short: change your style of play to account for teleporting, but always make sure you play how you like it and not how RAW prescribe it.
Pretty much likewise. As it stands, teleportation isn't too difficult. What it is is dangerous. We ruthlessly enforce Finesee rolls for teleportation (harder out of L.O.S) which makes Teleportation very useful, but not an everyday option.
The regio-boundary issue is always a tricky one, especially if you want to consider penetration. (I cast a spell in a magic aura, aimed at a priest in a dominion aura. What adds or subtracts where?) I'd suggest making it dependent on the regio. Some are sealed, permitting travel between levels only when certain circumstances are met, others are open and anyone can wander in. It preserves the mythic feel without causing other problems. If spells and arcane connections can't be used across regio boundaries, magically contacting many covenants becomes impossible, after all.
Fifth Ed. teleportation is extremely dangerous unless one is a Magus casting the spell or has the rare good fortune to be the subject of a spell researched explicitly for one's use. Otherwise, every single last use of it causes Warping to accumulate, potentially taking an effective year off your Longevity Ritual-extended life.
Hermes Portals are now some of the worst investments in the game. What used to be permanent enchantments that could criss-cross Mythic Europe now require an investment of 30 pawns PER YEAR to keep any given pair open and will inflict 1 Warping point per transit through them. Unless you're planning on shipping huge quantities of mundane materials, they aren't worth it. Even then, I'd recommend developing and Mastering Level 50 spells (max. possible without becoming a Ritual) for shifting large Groups of individuals and their cargo, using relays across the land.
Hermes Portals are just the ritual that is commonly known in the order. What you're looking for is Mercere's Portals which are invested devices rather than rituals. They still criss-cross Mythic Europe and don't cost any vis to upkeep.
The rules and description for them are in Houses of Hermes: True Lineages. Their method of construction is considered a house secret by House Mercere.
If you haven't done so, I highly recommend reading HoH: True Lineages. A great deal of "Mythic Europe, the 5th Ed. version" is presented in this book.
We HRed it to 'anything with an arcane connection to you doesn't need casting requisites, so long as you're touching it.'
As far as I recall, you can't force an arcane connection without spending some time and effort on it, so it prevents you from grabbing The Ring off the pedestal and teleporting home safely in an instant.
We also enforce a Finesse for unobserved locations, uncertain placement...
Sounds like a sensible HR if looking to ease teleporting. I've always prefered the coherency of the metaphysics (that moving a From requires said From as a requisite), but the main point here is that if feeling that teleporting is to wasy, than not HR those requisites away is a sensible way to keep teleporting challenging (and theme/story-provoking).
Actually, you're house-ruling them in. No requisites are required to teleport with your clothing etc, since the rules don't mention them. In the same way, requisites aren't required to lift someone three feet and take their clothes with them. It's magical motion, one is just faster than the other. Wormholes and space-bending don't exist in Mythic Europe.
That said, a requisite would be required to teleport you and anything you can't comfortably lift (since a normal motion spell would pull you away from it).
That said, teleporting anywhere which hasn't been specifically prepared for it is sodding dangerous. You're going in blind, and have a hefty chance of losing limbs if something has changed or you screw up a Finesse roll. It might not be very difficult, but it's definitely not a cheap trick.
It's a funny thing, since personal wards will typically protect your clothing as well as your miserable meat, as does the Parma Magica, which is helpful for keeping someone from igniting your clothing while you're in it, but leads to the question: What's so special about your clothing?
Again, we figure it's the arcane connection it has. Therefore a weapon you just picked up won't be shielded, but that Wand of Lightning Doom you keep in your pocket has enough of you rubbed off on it to be protected, so long as it's in contact.
Ah yes, in either case, we also require that you carry whatever it is. Simply sitting on a statue you made isn't enough, you have to make yourself large enough to carry it or else simply use a ReTe touch teleport on it.
We just reason that it's attached to you so it moves when you do, in the same way that ReHe can make a carpet fly even when there's a rock on it. The fact that the movement is instantaneous doesn't make it a new kind of movement, just a very fast kind. Not that this is necessarily ideal for the wizard, since a magus chained to a rock can't necessarily teleport away carrying the rock. Doors, etc, tend to get ignored in this logic. Re does that sort of thing, y'see.
That's an interesting idea, but if something disappears I'd rather believe things above it would fall down. Besides, think how easy it would be to ReHe masses of goods that way. Get a big enough carpet and just teleport your cargo, with no apparent limit on how much if you stack it well enough. Arcs at least require some time and effort to develop.
The logic is that if you can move it freely and the things on top move, then both can. If you can't, they don't move. If you can't move the carpet then the things on top don't move either. Obviously, this makes moving a wagon desirable but by then you've got to deal with size modifiers as well.
Or, indeed, use the requisites. A carpet with a small rock is ReHe and the rock moves. A carpet with a tonne of rock on top requires ReTe to move the rock. A magus hanging on to a rock just gets pulled of it. A magus under a rock is trapped.
This is an argument seen in relation to other subjects, but the logic is flip-flopped - if it should be exempt from the general rules then it should be stated explicitly and not the other way round. I'd hate the books to have to spend valued space on repeating the basic rules at every twist and turn. They must be taken at face value.
As for the comparison with Parma Magica for argument, the effects of the Parma and spells cannot be compared. First of all the Parma is not described by the same parameters as spells (so comparison with e.g. Target Individual is not granted), secondly the Parma has no Form thus has no capacity for requisites at all, and thirdly the description of MR on p. 85 explicitly defines what it covers (which includes clothes).
As for the comparison to other ReCo spells to lift, levitate or similar, it is my opinion that is quite different from teleportation - in line with Fhtagn's example of the floating carpet, except that I do see teleportation distinctly different.
Having said that, it is my impression from other threads that not applying requisites to teleporting is not a rarity - and in the line with this thread, I suggest anyone feeling teleporting to easy for their particular tastes to include such requisites.