Darn, didn't see this thread soon enough. I'll just post here what I wanted to post as new thread a few minutes ago:
Improving Teamwork: Citadel Upgrades
Citadell upgrades can easily turn the tide in a match but it is hard to purchase them at the right time at the moment and to plan ahead if you are not on VoIP.
1. You can't see which citadell upgrades are already purchased if you are not in your base.
You can't tell if one of your teammates has already purchased the gold or building health upgrade unless you run back to the citadell. Sometimes I go back to purchase a crucial upgrade only to find that it has already been purchased and maybe you don't have enough gold to purchase the next logical upgrade.
It would be very helpful if you could display the citadel upgrades at any time to plan ahead and get the upgrades for gold, catapults and giants as soon as possible.
2. You just lack a few coins to buy the upgrade you really want.
Your teammates and you have enough gold to buy giants if you would throw your gold together but you can't buy them just yet? You could sell some gear or drop something for a teammate to sell but another solution might be easier and more player friendly. Why not buy half now and half later? (upgrades in image are chosen arbitrary)
Instead of purchasing the whole upgrade at once you could just buy half of it and your team can pay the rest. Of course the upgrade only becomes active after it has been purchased 100%.
3. Suggest a strategy.
You could suggest the next upgrade to your team this way too. Maybe there is a newbie player in your team and he is not sure which upgrade to buy next. If he sees the half-purchased giants upgrade...