YEAH! :DI think you mean "ram only"
Make it available at the TC as well. That way, it can benefit TCs which can't handle siege. It'd be a minor change that will improve balance. Currently, a ram+40 Hun CA show up at your TC, its dead. And this can go a long way towards dragging the Huns into imp and then defeat. No one but Huns will probably be affected since they're likely to produce rams as they have no onager to upgrade to in imp. So if a game reaches such a level where the Huns abused their OPness completely, they can at least get a bump to the ribs.Heated shot boosting normal towers vs siege would be better, since those towers are underused in other than Feudal Age (especially Dark 11).
Heated shot boosting normal towers vs siege : NO, Why you want to make game more defensive?
BBT getting bonus vs Rams : Hell NO. Rams are the only counter to BBT other wise people will make 100 carts and spam BBTs along with 10-15 bombard cannons to kill trebs. How will you beat that.
Displaying civs at the start screen : Good idea and beneficial. Not sure how difficult to implement.