Full refund is typically if you can't get the game to function properly even with the help of Stardock support.
But you may be able to get the 75% refund if you don't like the game in its less buggy state.
Honestly, with the modability of the game and the fact that the expansion itself might be a superior game, and the strides that they've made in improving the game itself (Since this is the first game on a new game engine) I'd keep it just for the two expansions. Plus if someone comes out with a really awesome mod, you might keep it just for those.
But it's up to you. Someone else posted the email address already, and good luck whatever you choose. While the release itself was disappointing and the game mechanics aren't quite what I thought they'd be (I'm composing a list of advertised/dev blogged mechanics, how I interpreted them, and how they actually work in-tame for later posting) I have regained faith in Stardock for their efforts to fix the issues. The launch was trashed pretty well mostly due to bug issues, which have been addressed majorly. I still have CTD's but much less often. Now that the bugs are pretty well shot from 1.1, I'm excited to see if we have a well balanced rock/paper/scissors RPG/TBS game (Even if it's somewhat vanilla, it's a rare game type recently) by 1.15 or 1.2.
If the two expansions don't rest your concerns, you're out $50 (Or a little more if you're like me and bought the collectors) and you've learned a lesson. If they do, then you've got a decent game (Or three if the expansions are that radically different instead of just stand alone) or even just one game if just one of the expansions is good for you.
If you've not missed the money this far in, maybe give it a little more time. If you're like some on the forums and decide to rebuy later you'll be paying more for the game+expansions.
I'd only get a refund if you need the money. I've bought bad games for XBox 360 and PC several times, but I just considered it lesson learned. I remember the excitement of Neverwinter Nights 2, getting to the final battle, and having a game ending bug that got stuck in my autosaves. It killed me and I lost my desire to keep playing.
Or Mass Effect (360) and that long race down the corridor in the vehicle. Right after I spoke to the AI and started again (After about ten hours of strait playing without the autosave on) down the tunnel, the thing froze. I never finished ME. Though I did buy ME2 and play through it entirely.
It's up to you what you do. But that's my thought.
Elemental Forums
Stardock Forums