Well, perhaps my confussion is due to the fact that I haven't still BI (nor the patch 1.3).
I've read a lot of things about the new features of the expansion and about the new problems for modders, but I'm not sure what you people are speaking about.

Which of those features and problems are particular to BI and which ones are common for BI and RTW 1.3?

One example: it is said that it is possible now to include new cultures (religions?) and change the assignation of the factions to those cultures. Is that true for RTW1.3?

Another example: horde factions. Are they possible for RTW 1.3? Perhaps I would envisaged this feature for factions such as scythia or numidia.

One more: are the problems with .hgt file only for BI or also for RTW1.3?

Last (but not least) for the moment: can victory conditions be changed in RTW1.3?

Sorry if these questions seem dumm , but I'm a little