How to deal with rebels?

[Gilrandir]

The Welsh are the only faction I haven't played in VI. Archers just aren't my thing.

Did it once and, well, saw it through. You should attack Mercians and capture Mierce before they start spawning Huscarles, that is before they build the fort (4 years) and the royal palace (10 years, IIRC). It wasn't a problem for me. The problem was Saxons, who did start spawning Huscarles. Yet the key thing here is to have many-starred generals.