After a bit of playing, chatting and thinking about the game, I've come up with a few bits of feedback:
Add animated tiles for maps, like a small flowing creek, bush/tree with leaves moving with the wind, occasional birds flying over/circling.
Add the possibility (or document how in the manual if it exists) to add own music to the game.
As posted above, sound bits for soldiers. Hiring voice actors may be costly, you could include the option of adding sound files for the community, so they can record / copy their own British, US and German voices. This could be an addition to the Force Builder.
Turn the "H" option on by default, with a switch in the Options (which sets the default for every started game), but leave the possibility of manually toggling it with the H key. I see many people struggling with cover/resupply because they don't see enough GUI information.
Add (Xerkis'?) weapon stats and soldier (Force Builder) options to the website in a nice grid. I like to see what I will be using in a game I'm interested in buying, and for those already owning the game it is a handy tool to have open besides the FB.
Make it possible for players to upload their Forces into the website, so they can show & discuss their creations. Alternatively, make a web form with the same options as the Force Builder, and the possibility to extract the results to your FB. This should distribute and level player skills more easily, as we're able to copy each other's tactics, counter them and improve on them. Also a good incentive for interested buyers, seeing how interactive and fun sharing and modifying troops is.
Link the customized AI tables to the Force Builder. If someone is very good in creating custom forces with matching AI (again, Xerkis

), he'd be able to share those with the community and improve everyone's skirmishes. Not everyone is willing to or adept at fiddling with game files.
Include the cover story for each map, or create one for non-historic maps. This should increase immersion.
Add a "remaining ammunition for current weapon" indicator to each solder. Perhaps mention in the battle log "Pvt. Johnson is using his last magazine". I like to know when I have to start moving my squad towards an Ammo Dump.
Add a MP "chat lobby" where we can discuss pre- and post-fight details. I'd like to know in advance what kind of game someone is hosting, or find someone of my experience level. Afterwards I'd like to discuss how the battle went, exchange tips and counter tactics, and plan a rematch.
Now, it's a bit like taking a woman home, having some intensive action going on, then just kick her out without exchanging a word. I don't know about you guys, but I just don't do that - not that I'm judging anyone's habits

Or, as I suggested elsewhere, link TA with something like Gamespy. This allows me to watch a movie while keeping an eye on an application that tells me when an opponent comes online. Or have it play a sound when that happens.
Add the option to name/describe a MP game. I'd like to be able to name my session "newbie testing out newly created squads", so someone looking for a thorough challenge won't crash my party.