None of these suggestions are that significant, but they're all little things that could make the game more convenient for some players:
1. It'd be nice if the status icons that appear on the "My Games" page next to the players' names also appeared on the actual game pages. That way if you refreshed the map, you could see at a glance how close it was to your turn.
2. So far, I've accidentally hit the [End Attack] button once when I meant to keep attacking, and I know that two of my friends have done the same thing. It might be helpful if there were a checkbox to the right of the button that had to be selected for [End Attack] to work. It'd mean a tiny bit of extra effort to click each time you wanted to end that phase of your turn, but I think the reduced chance of accidentally ending it early would be worth it.
3. It seems to me that logins on this site time out very quickly. It would be a nice feature if there were a way to extend that, maybe with a checkbox on the login screen.
4. A lot of folks use tabbed browsers, and if you've got two games open at once. it's hard to tell them apart in the tab bar. If the game number or the name of the map being used (or both, even) were near the beginning of the page's title, then it'd be more obvious which was which.