Come on man, you know you're overreaching by suggesting we all ride Light Cav essentially naked.
That's exactly what you should do if you have problems economizing. It works.
This entire thread is about "I want good horse, decent armor, best cavalry weapons, and I want it every round". This thread isn't about balance at all. It's about people who want to be overpowered constantly and feel it's their human and natural right.
You can play as cavalry every round. There are other cavalry weapons besides Heavy Lance. You can poke people with cheap spears too, like a fork, believe it or not. There are horses that are cheap. There's cheap armor. Now you just have to optimize and select best option based on upkeep limit. If sustainable limit is 20,000 gold, you pick equipment for that. If it's 40,000 you pick for that.
This thread is ridiculous because some of you refuse to see. You close your eyes and shout that it's dark. You refuse to acknowledge that cavalry can be successfully played without top gear. Well I'm sorry, the days when every grinder could charger in in his plated charger, raise hands and sing a song, and enemies would fall down trampled and die massively - these days are thankfully over.
I think the sumpter would give you bad habits, it is a really bad horse.
It's still a horse, which can be huge advantage if you use it right.