I don't know if these are really technical questions, but...
1. Depends, as of right now I think its a little bit expensive for what is provides. Now if they end up putting in scenarios or better multiplayer features that aren't in the current beta yet it may well end up worth it. If not, certainly won't hurt to wait for a price drop, at which point the game will be better patched an their will be more mods available anyways.
2. Don't think so, but they're really trying to optimize it.
3. No, but as you have trinity you can get a $10 discount.