I'm comparing it to existing CR 8 or CR 10 monsters. I'm all about upping the ante on giving character classes solid, tier 3, level appropriate options, including damage dealing, but when it comes to designing monsters I try to keep things in line with comparable CR'd abilities. 7d6, an average of around 25 damage, as a ranged touch attack is quite large for a CR 8 to be able to throw around at will.

Also, your examples are both using full attacks and both using melee, non-touch attacks. Let's try to play the same game here.