How does the multiplayer matchmaking work in Shogun 2 Total War?
Solution 1:
The advantage is actually not that great. If you play a lot you do get more retainers and more experience for your general but it's overall strategy and tactics that will win you the game. My general currently has 8 stars and I remember when I started off I beat a 7 star general without using any veteran units or retainers.
As to how the players are matched, if you let the game manage it, it will try to find a player of your level if one is available, if not, it will keep searching for any available player of sufficiently close rank.