I need a FULL list of something...

[Ludens]

Do the new Mediaval Factions have units that they only have? Because I could make them playable in 1.1.

No. The Aragonese have the same line-up as the Spanish (both get Spanish Javelineers), the Sicilians are a standard Catholic faction with Italian/Byzantine ships. The Hungarians do have two unique units: Jobaggy (cheap but weak javelineers) and Szekely (excellent horse archer unit: fast and better-than-average melee stats).

[Mouzafphaerre]

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If you're into mods, the Modlet initiated by yours truly rearranges unit availability among a few other things. (The unfinished beta will be released -hopefully- shortly.)
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[elbasto]

In my opinion several tweaks to the campaign makes management easier to handle and that's the part of the game that I personally enjoy the most.

[ezoons]

With VI, I can now quick-save before battle (once the army match-up screen pops up). I'm not a fan of save/load-ing but sometimes I have to fight several battles in one turn and just don't have time for all of them

[Kekvit Irae]

The VI campaign is a refreshing change from the vanilla MTW campaign. No pope to annoy you, plenty of border disputes, and a faction (Vikings) that wont go away and cant be conquered (by normal means).