Couple of ideas for brainstorming with..
1) 'lite' option for new players first couple of chars..
Automatic oath to random lord in realm but funded a small amount per week by fictitious 'sponsors'.
Automatic assignment to largest army.
Option to move to 'full game' available any time.
Prestige/honour/gold/bonds/unit/stats size cap for balance.
2) Tutorial
Basically an optional scripted tutorial with tasks and achievements that happens between char creation and entering a realm. Maybe a little honour/prestige/gold for doing well. Could include anything a char needs to know. Could be lectures/quizzes or practical tasks as warrior, courtier, infil, priest, lord etc.IC played as noble's education. Done well could be fun and impart a lot of information but it's a lot of work to do in-game. Could be done as a stand-alone mini-game or even a basic quiz site, though.