A lot of people requested it, but maybe Larian didn't want to introduce new gameplay mechanics at the last minute, because the game was designed to let you skip all the RTS battles, and even if you play them, you can skip playing as the Dragon too.
In their Divinity 2 behind the scenes video, they mentioned that initially, they wanted an RTS at the end to be part of the final battle, but that meant they needed to teach players the mechanics and such.
It would make sense. I'm not sure how could be implemented without "killing" the game flow, but the idea of a final confrontation with Corvus is tempting ^_^
Having to deal with an enemy dragon on the final battle would have been fantastic and would have really finished the game off right. But Act III as a whole was pretty bad. Final battle I just dumped around 30 unit's on the country and it was over.
Course then the final insult from the Devs was not being able to speak to the wife after the victory was won.
I don't know if they just ran out of money or time or what, but a little more work and this game as a whole could have been bumped up a few notches in the ratings.
I have just finished the game and I agree about the little polish here and there... but frankly, I believe the final result it has been fantastic; maybe it's because I wasn't expecting much, but I have enjoyed it inmensely.
I liked the ending and the final chapter. Maybe I was expecting that final battle in dragon form... but I have not been disappointed ^_^
