Marko Markoko makes an important point which needs to be out in the open: the cosmology of 5th Ed. is dramatically different from that of previous editions. Early editions emphasised a struggle among competing forces in the Mythic world, with the older Powers striving to hold their own against the encroachments of the Dominion and the Infernal. Multiple models were suggested, and resulted in different treatments. Occasionally one would have a "wild card" sourcebook which defied the logic laid out elsewhere, such as "The Hidden Paths: Shamans". Overall, however, the implication was that different myths existed and were "true" to varying degrees. Including non-Judeo-Christian-Islamic beliefs.
Fifth Edition radically emphasises the Dominion as the Absolute Truth of the world. Which version of the Divine may be the One Truth is debated, but what is not debated is that it IS the One Truth. A One Truth which has a profoundly negative effect on practitioners of Magic and the forces of Faerie, not just its ages-old adversary, the Inferno. ShopKeeper John, if this doesn't inform Magi of the disposition of the Divine toward their Arts, I'm not sure what would. Magic becomes a thing to be used and experienced only apart from the community of the Dominion. Within it, within the supposed precincts of the Divine, Magic suffers harshly. For those who perceive the world with their Magic, who know it as an intrinsic part of themselves, this seems to be a patent rejection of that side of their nature by the Dominion. The bitter irony is that the Inferno is LESS of an active opponent of Magic than the Dominion. In the scheme of the One Truth, Magic seems to be judged closer to the Infernal than to the Divine (at least in 5th Ed.).
The problem herein is that it quickly becomes difficult to address the issues without tackling religious beliefs and theologies which extend into the modern day. Which is one of the reasons why I've tried to confine most of my comments to the tangible effects felt in response to the dramatic strengthening of the Dominion against all other Realms instead of addressing the other point more directly.
I say again that the magic-deadening effect of the Dominion in 5th Ed. has been wildly underestimated. Extend, for a moment, beyond Hermetic Magi, who can accumulate vast Magical Power and hold their own. Consider the case of those with Supernatural Abilities as they are just beginning to discover them.
The threefold negative effect of the Dominion is extremely harsh on all Magic- or Faerie-derived Supernatural Abilities. Let us examine Second Sight and Dowsing, two of the most common Supernatrual Abilities in Mythic Europe. The nominal base Ease Factor for either of these is 9 in a Mundane (0 Aura) environment. Under the pervasive influence of the Dominion, this increases to 12 even in the Countryside--making the very first awareness of an ability a Hard task. For those who dwell in villages, it is a Very Hard (Ease Factor 15) task, and for those in towns or cities, Impressive (Ease Factor 18). That's for the Magic-derived. For those with Faerie-derived Supernatural Abilities, the impact as even more severe, going all the way up to Impressive (Ease Factor 21) in the cities. Someone with Susceptibilty to the Divine would almost NEVER be able to utilise their powers, with base Ease Factors of 15, 21, and 27 in the countryside of the Dominion, in villages, and in towns/cities, respectively.
Now, keep in mind that these are the minor talents starting out. They are untrained, meaning a base score of 1. Unless they have strong natural Perception, they will almost invariably fail at the most basic of tasks within the influence of the Dominion. In all probability they will be unaware of their potential, never having a chance to develop it. A prospective teacher would have a very hard time identifying a potential pupil because the pupil's Ability would, for all intents and purposes, almost never manifest. Within towns and cities, Supernatural Abilities deriving from any other source than the Divine/Dominion are suppressed. This suppression would prevent the Abilities from being discovered/identified in the first place, leading to a sharp drop-off in the frequency of their practitioners.
This is the effect on the most common Supernatural Abilities, at their most basic level of use. More difficult uses are even harder. The ineluctable consequence is that people with the potential will not have the opportunity to realise it if they dwell anywhere within the Dominion, and those who have any meaningful Skill will probably have had to leave the Dominion in order to pursue their studies. Imagine the difficulty of engaging in any form of Practice when one has a minuscule chance of succeeding at the most basic task, and the risk of botching may actually be higher.
It would be difficult for those on the outside not to notice the paucity of any Supernatural Abilities within the Dominion. Those with the Gift would have a very hard time developing any Supernatural Ability on their own, and if not for the disturbing effect that they have on their surroundings, might be next to impossible to find (this is one of the few things I can think of to justify the Hard Ease Factor for locating a prospective Apprentice when fully 1 out of every 10,000 people has the Gift in 5th Ed.).
Pyrisus of Flambeau's case is thus made very firmly. The Dominion is steadily removing Magic from the world. Something has to change or else only the strongest Magics will survive--and for how long? "On Defying the Church" is a case made in desperation and outrage against this progression and loss of the birthright of Magic.
In an effort to "tamp down" the power of Magi, 5th Ed. catches hedge wizards and minor talents in a very broad and oppressive net. I would contend that in efforts to promote the Divine and the Dominion, 5th Ed. actually serves to make the Dominion a far great opponent of Magic and the Order than ever before.
As for why I'm arguing the point here instead of just relying on "house rules", what's the point of having a common, "official" set of rules if one is increasingly forced to rely on "house rules" to make them work? Fifth Ed. has straightened out some things, and introduced some new, fascinating rules (I rather like the changes to Spell Mastery, and the use of Sympathetic Magic in association with Arcane Connections is very good indeed), however, there are some serious changes to long-established, fundamental rules that have consequences which seem to have either been ignored, overlooked, or disregarded. Realm interaction is one of the most pervasive, and thus one which I feel must be addressed.