Fire sites underwater?

[PyroStock]

Also, there seem to be less 'valuable' sites underwater

I agree in full on this. No really cool underwater sites adding nice indie mages and such (those that excist usually gives water, something water nations tend to have).

Agreed.

Also so far I have never found an UW site giving any bonus in the various magic paths either.

I found the Arcane Gateway (-20%Conj bonus +1S) and Water Solstice (-50%Ench. + 4W2S) both in the same water province in my last game. Excluding Blood obviously, I don't think most of the path bonus sites are restricted to land only, but I haven't looked.