First of all, I've long been a fan of your work. I've owned each of your galciv games buying them on or near the day of release. As a long time strategy fan I appreciate what you do.
I've played two DA games. Not as many as some I'm sure, but enough to collect a few impressions for anyone interested:
1. Mega Events (ie. Jagged Blade) -- This event has been commented on in other posts, but I'd like to add a few words. First of all, I am a big proponent of anything that adds late game excitement. As most people know, games like this and the Civ series are usually decided well before mid-game even if there is quite a bit of mopping up. On the other hand, this is also when you want to play with the new toys you've spent the whole game building. But without an end-game challenge, I never finish most of my games.
The big problem with the Jagged Blade event is that it just isn't fun. You may remember one change that was made from Civ III to Civ IV was that pollution was removed. They realized that while their implementation of pollution represented a real challenge that added to late game complexity, it WASN'T FUN. So they took it out. And most people felt this was a great move.
My suggestion is an event that consolidates several weak powers rather than one that creates a new one out of several civs. (Perhaps such an event exists and I just haven't encountered it.) I can't count how many games of Civ or GalCiv I've quit because the opposing empires just didn't look strong enough to make finishing the game seem interesting. Perhaps the event was designed to be balanced for multiplayer. As someone who primarily plays against the AI I tend to think that way.
2. Planet Civ Techs -- I think this has been commented on elsewhere, but the AI is way too hungry for these. I was able to turn these techs into 20k credits several times in my games (largest map with max number of major and minor civs.) It is particularly silly for the minor civs to be willing to turn their entire 6000 credit treasury over to me for these given that they never colonize.
3. The new planet types -- I am generally a fan of this decision. It slows down the fast expo if nothing else. On the other hand, now that you've gone to all the work of adding the techs and icons for these, it seems like there should be more to the planet types than just when I can colonize them and partial penalties until I research the appropriate techs. Specialization makes planet-building fun. This is why people were mad when the tile resources disappeared. My suggestion is that the planet types have long-term bonuses or penalties (like 5-10% to research or production) to give us something else to think about as we plan our empires. Perhaps something like this exists and I just haven't seen it in the documentation.
4. Surrender -- I was playing a builder style hiding out in my corner of the map, when suddenly, two civs surrendered to me that I had only barely contacted. I had never traded with them and hardly had any contact with them. I assume that they were being demolished in wars with other civs and my relations were higher than other civs, but it seemed really bizzare at the time. Suddenly I owned about 40% of the map in my nine player game. I tried to replicate this with save games and they didn't surrender to me again, so perhaps it was just a freak event. Either way, it was weird.