How so? I'm asking because I'm curious, not because I aggresively disagree.
Theurgy is high ceremonial magic - in many ways much closer to historical "hermetic magic" than what we normally use.
It focuses on names and ceremony - and on gaining access to power by invoking those who have more than you.
Admittedly, some of the entities it invokes might be thought of as faeries (in that they are pagan gods), but these are not the main "targets" for you invokations. Instead you'd invoke the myriad of other "higher spirits", eg. the titans and their ilk.
A much less upper class tradition of magic, spirit magic mainly deals with spirits weak enough to be bound to the caster's will. But even these entities are (sometimes) sentient and may earn the friendship of a magus. TBH I rather liked how this was treated in Legends of Hermes.
First off, I have mainly experience with Theurgy - we're only now introducing a user of Spirit Magic, so some of this may not be as applicable to spirit magic as to Theurgy.
Firstly you have to consider how easily available you want "new" spirits to be.
If it takes a quest every time you want to invoke a new Daimon, just to get info enough to invoke it, you'll have a pile of stories, but they are likely to be ones only the theurgist cares about. If you can invent an Invoke spell for any Daimon you like, fewer stories will be generated, and the theurgist will be more powerful.
And how about True Names of spirits - a x5 multiplier for penetration! If I want to summon Chnobis the Serpent (might 30) I will need a spell no less than level 31, but if I want to call him in a single go, I need a spell of level 60 - and in either case, I'll need to penetrate a might of 30!
Having his True Name makes this much more easily done, but how avaiable are these True Names?
Do you need to know them to Invoke the Daimon at all? That would make sense, since it's one of the few ACs you can (reasonably) obtain to Daimons.
NB! Daimons do tend to gain power from being summoned and are generally hard to truely affect, so they actually have relevant reasons for not completely concealing their True Names.
The same consideration goes for Names of Power (and especially Invocation major mystery).
How easily can you obtain the Names of relevant powers? Is "Isis" good enough to let you call upon the powers of egyptian goddess of weather, magic, healing and childbirth? Or do you need to quest for a secret Name for her, known only to the secret remnants of her priesthood or perhaps written down in plain sight - but in a language no living person can read? Will you need a different secret Name for each of her aspects?
And how much bargaining will you have to do with each Daimon once called?
They gain from being summoned and so are likely to arrieve positively inclined towards the magus. They have very little to loose -even if the given avatar dies it barely affects the Daimon itself. But they might well still ask for services of various sorts.
In short, there is plenty of potential for stories here, but many of those stories might well matter very little to anyone but the Theurgist himself.
One other note of import is that Theurgy is not actually very powerful, compared to the main thrust of Hermetic Magic. Mainly it allows access to a few tricks not normally available to hermetics, but at the cost of a wider growth. With regards to the Titanoi of house Tytalus, the joke goes that Tytalii don't use Theurgy because it's an easy path to power. They use it because it's hard!