Capture is pure @#$%, even with men inside you can't defend a barack or a cc. Up the garnison defense by troop.. please .
We need also have a reflection about what players want about towers sytems.
about nerf champ cav melee, not a big nerf is needed, we don't need fix the issue right now, just mitigate the issue. A little nerf damage and delete HP tech 10% and hp tech for selucid and perses is enough for have an opinion.
About giving little bonus to each civ, for me it's bad, it too much age of empire 2 like. but as you want. I prefer we have a commun tree tech and some difference (unit, building or bonus).