After playing MTW for more than a year, I have a strategy for avoiding rebellions that works.
1) Build the Capital Province up so that it can build Royal Knights. Do not build palaces in other provinces.
2) Keep all princes in the Capital Province
3) Build Royal Knights and place the Provincial titles on them and leave them in the Capital Province. Any new provinces simply build more Royal Knights and leave them also in the Capital Province.
4) Marry the princesses off to these Royal Knights.
5) Keep loyalty in the province at 200%
This strategy works because the Royal Knights have the highest loyalty.
I never get a Provincial Rebellion or a Civil War.
What do other people think of this strategy.