I'm moving the discussion which has developed out of "Hermetic Demographics: Where are all the Quaesitores" here because it's getting off the intended topic of that thread, while growing out of it. For those interested in seeing the comments to date, check that thread.
Ok, I have a few things to say regarding the preservation of continuity. I respect the fact that each edition will choose to emphasise certain characteristics over others. In a way, previous sourcebooks often had a degree of "filtering" in their perspective, though many of the later 4th Ed. books in particular offered individual Sagas several different possible options to choose from, letting them decide which of the described scenarios, rumours, and, in a few cases, "facts" were true and which ones were merely the tales whispered in the setting. To some extent, I have no objection to this, as history is often a muddle, even when records are kept. Do we really believe the spectacular triumphs proclaimed by Thutmoses III in his battle against the Hittites? Or do we believe their official records, which have also been recovered? Even within the Order of Hermes, with Redcaps, Bonisagi, and Quaesitoris actively scribing histories of events--to say nothing of the other Houses--there will be disagreement as to the "official" explanation of certain events.
Some things, however, cannot be contested. The time frame of the Schism War, for example, or the accompanying Renunciation and eradication from anywhere except deepest secret of House Diedne. The names of the Founders and their general characteristics.
But history is far larger and more complex than that. Sometimes there may be revisions to existing material which can, with some small effort, be justified or rationalised. E.g. the number of Quaesitores active in the Order. It's harder with the number of Gifted Mercere, as there are only supposed to be "about twelve", and we already know the names and locations of seven of them (Insatella at Harco, Viator at Ungulus, Mary and Rogitien at Rorschach, Susan of Whitlow at Three Lakes, and Simon at Venti Rosa). Stretching the numbers largely requires the explanation that it only counts "legitimate" Gifted Mercers of the Founder's own blood lineage, whereas any others are "illegitimate".
Then we hit major revisions. I haven't yet read the "Houses of Hermes" book describing House Flambeau (it's on my eventual reading list), but I've heard that, somehow, Delender, his tutor and master, who was described at great length in "Tribunals of Hermes: Iberia", has been excised from history. How and why? More to the point, this constitutes a severe revision that verges on a break with canon. It is an established fact.
Other changes result from the new edition's rules treatment. Magic Resistance is one of the most (in)famous. I don't want to get into that, here. I'm merely citing it as an example. The removal of the Permanent Duration is another, and one which I cannot fathom, especially since new Durations/Ranges/Targets only rate as Minor Breakthroughs, and Permanent effects are the sort that Magi would certainly have been seeking from the start.
Then there are specific details of Houses and Tribunals' history and character which have been stated in previous editions which are "forgotten" or completely ignored in subsequent publications. This is especially troublesome when the mention was repeated in multiple volumes of previous works. There is a cumulative canon which is being set aside, leaving those who have built off of them, or who might seek out the older works in the position of having no idea of what is canon. This is why I say that it must be preserved whenever possible.
I want to address some of Mr. Ferguson's stated objections regarding the need to recognise previously published material reducing the author pool.
Atlas Games should have a copy of every single sourcebook every published in the game. Acquiring old copies from various sources is not that difficult in this day and age. One would think, therefore, that it could compose a "writer's bible" which would include all pertinent details. If nothing else, the editors should have access to the works, and should have a good memory for what has or has not been said.
The fan base is large enough that anyone working on a subject could simply ask others whether they can recall anything which might be pertinent. This could produce a list of recommended works which the would-be author would find very useful, and if only a side mention is made, this can be gleaned through these sources and then confirmed by the editor.
I've seen a massive timeline compiled using almost every date and figure in the accepted canon. Works like these, done by diligent fans/players, are invaluable resources. They help preserve the continuity, and can also spot alternative junctures where things are in conflict, allowing for future exploration and/or resolation.
The old edition game books are now much, much cheaper than they were due to the presence of the new edition. If one is patient and interested, it isn't that hard to acquire the key works at a discounted rate. When working with Houses, for instance, one should have both the "Order of Hermes" and "Houses of Hermes" (4th Ed.) to know what has already been said (alas, I must confess that I haven't been able to snag these). Of the two, the latter is probably the more pertinent, since it is integral to 4th Ed., which seems to have the greatest range of actual sourcebooks as opposed to adventures.
Ultimately, the question is whether the intent is to preserve the continuity of the game, embellishing, consolidating, and streamlining the grand canon which has been created, or whether the intent is to break with the canon of previous editions in order to "reenvision" it. Fifth Ed. seems to be a mix of the two, leaving the question of what is canon in doubt. Unless it plans to rewrite all of the major sourcebooks (including the Tribunal books, as these are key) into the new edition--invalidating the previous works, many of them good, some not--there needs to be a clear set of guidelines in order for players to gauge what to trust and what not. And an explanation of why those changes were made.
Thus far, of the 5th Ed. books that I've read, "Guardians of the Forest" stands out for its extreme respect for previous canon. "Houses of Hermes: True Lineages" has a number of excellent elements (including, yes, the House Tremere section, as it finally shows a House with strong Classical roots--true of House Mercere, now, too), however, some of it doesn't mesh well with established canon. It lives up to a standard of high quality, however, these changes to the canon can be distracting.