This is my first gen as 1h cav, but I've finally started to get the hang of it and get really good kpd. If you're on NA and you're strictly a 1h cav, 5 ride is a good way to get fucked by all the lancers. I'm sure it's worse on EU. So I've been doing pretty well with 7 ride and a Well bred Arabian Warhorse. Only coursers can catch me and they have a hell of a time hitting me anyway 'cause of all my maneuverability. Also, after the huge nerf to horse's legs every horse can be 1-shot. With the Arabian I can turn out of the way at the last second if someone spots me. The only thing I have to watch out for are bows, xbows and throwers, though they have problems hitting me also because of my maneuverability.
Here's my build:
15 str
21 agi
5 if
5 ps
6 shield
6 ath
7 riding
0 wm.
111 1h wpp
I've been using my MW broad 1h battle axe and have had no problems hitting people. Since you'll be bump slashing anyway, you'll be really close to the people you're hitting. And with 38 cut to the head at speed it's pretty much a guaranteed kill even with 15 str.
I have high athletics and shield 'cause I like to fight on foot a lot also. You could easily drop both of those to get 18 str if you REALLY need it, but it's pointless in my opinion.