Messages

Very important:
3. A strong bot.
2. A bot with a setting for different play styles
7. Option to invite specific players to your table

Nice to have:
1. An offline client, allowing you to play campaigns against bots
4. Options for timed games
5. Options for undo settings
6. Online mini-tournaments; the option to easily create one for you & your friends.
9. Better animations when cards are gained/bought/played/...
10. Better visualization of split piles, Archive/Crypt contents, Prince targets, ...

Don't really care:
11. Android app (or just improved compatibility?)
12. iPhone app (or just improved compatibility?)
14. Improved moderation (dealing with chat abuse, slowplayers, ...)
10. Option to hide the log
13. Downloadable game logs
15. Tutorial on how to play Dominion
16. Tutorial on how to play dominion online.
8. More translations (to what language?)