What's the easiest/best faction to control?

[HoreTore]

HRE for a blitzer. You can double your provinces in the first 5 turns taking Metz, Bern, Hamburg, Magdeburg, Prague and mabe Stettin, Antwerp and Dijon. After that, you can pump out armies noone can match and finish the campaign in about 30 turns.

Milan are also very easy.

[IPoseTheQuestionYouReturnTheAnswer]

If you take your time and are very careful, then I would tend to agree with the HRE, at least for raw potential. They are definitely a bulldozer faction - in my campaign, it's 1200 and I already control 71 regions. Expand fast in every direction and answer all crusades and carve out your own little kingdom of heaven and you've got everything going for you.

[Atalus]

HRE if you have some luck. England is a no brainer. Scotland Can be too if you thrash the English quickly.

Danes are pretty easy if you like that kind of warfare