If you want a one man army character do it. sure leadership helps, but once you get enough renown its not as important. I find being able to tear a hole in an enemy army all by myself is very usefull (especailly seige defense). But its up to your playstyle. Don't play someone elses way just cos it works. My guys only got like 5 leadership and ive got a max size of 260 from renown + feifs.
As others have said, dont fight alone at level 8 with 40 men. Become a Merc for a faction, its only 30 day commitment and follow the marshall around. Big battles but lots of other AI. After a big victory maybe raid a village or two for moneys (careful you cant stop once you've started).