Okay cav observations:
Horse archers: What the bloody crap? I play cav a lot, so I'll admit a good horse archer is a bane of my existence. But the treatment they got was just terrible and makes no sense. Horse archers rarely topped the score boards anyway, there was no problem.
Light cavalry: lots of horses got nerfed...I'm okay with that in a few situations, but I think the nerf bat was overused here. About all you can do now as light cav is backstab archers when they aren't looking (or are too busy raging over the archery changes). Cav vs cav fights are gay now. You are better off dropping your lance once you close in and using your sword. If you are being chased, there's not a good way to turn around, so why should I stop to engage the enemy cav when I can just keep backstabbing his archers? Like I said, gay (even though I'm sure you can still get some kills). The only positive is the faster lance thrusts now, which makes backstabbing archers even easier...
Heavy cavalry: seemed to get a bit of a buff on some horses, which was needed. However, now that you can't turn your lance around to your side, you can forget lancing infantry at slow speeds. You'd be better off just running them over or using a sword (which means you can't approach any skilled player who knows how to use a long pointy object). Honestly I haven't tried much heavy cav yet to make a more informed decision due to the higher upkeep costs.
It strikes me that the devs either a) don't like cav, b) don't know how to use cav, or c) are trolling us. I suppose the same can be said for many changes in this patch. This isn't a whine post, just stating the facts I see. For the life of me I don't know why chadz and co. want to make the game less fun and less balanced than it was before, at the same time.