It really depends if it is going to work like MTW / VI did. The VI game was quite seperate in terms of teh campaign, but the extra features were available in the main game if you wanterd to use them for modding.

That would imply that there WILL be extra factions possible for modding. OF course...you may just find that the total number available remains fixed, and you have fewer factions on teh map at the outset. The extras would arrive as 'horde' or emergent factions. Either way...the options for mod building are significantly improved. More options are always welcome!

Being able to mod religiona, and having more of the faction definitions in a seperate file will also make life easier for total conversion type mods. Improved battle AI is good too, though I wonder if that will be matched by improved AI choices in the strat-map element.

LOTS of bugfixes.....good! We all know they were there...and having them squashed makes it worth paying out for BI alone! I hope to see a full list of what got fixed when the thing is ready for release

And better moddability..... I wonder what the extended mod-system will be. Hopefully allowing mods to be more selectable in game, with a mod 'librarry' setup for ease.

Exciting stuff...and a load of new units too