Agreed on both observations. Waging war as in taking cities, especially on another continent, is very difficult due to the fact that siege weapons need to be ferried over, which is a logistic nightmare really.
Due to the high defence bonus in cities, actually taking them could prove to be tough even with high level units like level 3 cavs. However, to do damage in a war, there are other options besides taking/razing cities. Pillaging becomes a serious option should they choose to turtle up inside their fortifications, and would permanently damage their economy.
As for focusing on one unit, agreed again, the rock-paper-scissors approach makes one-sided armies very vulnerable to their counterpart... however, for cavs, their natural counter is the rifleman and they both are lightyears away from fielding those. A grenadier is actually the counter for the rifle, but vs the mounted cavs it performs only marginally better than a pike, as the cav is more or less the counter vs grenadiers.
So if I drop 12 cavs near one of their cities, their best bet (catapults aside) is to attack with pikemen, who still "only" manage to get a 110% bonus (ability + combat 1), vs my shocked level 3 cavs 35% bonus (60% if on hills/jungle, 85% if on forest). A not so good chance for victory there for those pikes, and what's even worse, even if they attack, they need to fully kill the stack in one turn, since otherwise I'll just move them back to my galleons again to heal up. A ton of catapults really is your only option, and even those would need to be placed in such a manner that they actually all could reach my surprise party in a few turn... and they have no idea where I'll be coming from.
But it is good that you try to dampen my (over)confidence a bit here, I'm gonna review everything some more when I get the turn again, to see what my best options are.
