Someone said:That´s true, but extremely unlikely. It would require a huge number of additional splatbooks allowed to cover most of the arcane list; additionally, those splatbooks (or parts of them allowed) would have to contain nothing else but new divine classes or new domains. It´s evident that at least some of them will have new sorcerer/wizard spells! Most of the new spells proposed right now from complete arcane and complete adventurer are sorcerer/wizard and don´t appear in any domain.
Of course new supplements will expand the archivist spell list; but have in mind that they´ll also expand everyone´s spell list.
I agree with someone. It's entirely unlikely and would require a huge amount of splatbooks with PrC's that are divine casters that have on their list spells which are commonly arcane, or domains that greatly break the divide. Both are very uncommon and with our current list of approved sources, almost unheard of.
It's incredibly unlikely that an archivist will end up with the entire arcane spell list in his prayerbook, much more likely they'll end up with a few arcane spells here and there at higher levels than normally accessed by wizards or sorcerers.
If someone would like to give a long list of clear examples which are going to break the archivist somehow to support the argument otherwise go ahead, that may help your case, but it's unlikely.