I wouldn't say it's gotten worse, I've been playing RTW (well, EB) recently and the AI does all kinds of really retarded shit. But yeah, it hasn't exactly gotten better either. They've made promises again, I'll believe it when I see it.
What has gotten better in leaps and bounds is the campaign game. They've done some great stuff in streamlining it without really losing anything compared to the old ones except unnecessary hassles, and actually adding a lot of good things. Removing governors, automated unit replenishment, automated garrisons based on buildings present, proper tech trees, removing diplomats, removing agent spam (and agent action spam as the only training method), multiple recruitment slots with variable training times for units, simplified building (some might not like this one but TBH I prefer it)... loads of great improvements.
There are some nice new bits to add flavor to battles as well, like unit special abilities. There was a lot less variety in those in the past. Nothing as groundbreaking as with the campaign side of things, though. Hopefully with RTW2 they'll bring it all together in an awesome setting. Some of the new stuff we've heard so far has seemed pretty interesting, but battle gameplay will be the main decider.