I think you underestimate how difficult it is to deal with a unit of 10 terminators. There are only a few assault units in the game that have a chance against them (Thunderwolf Cavalry, THSS Terminators, twenty or thirty or fourty genestealers, and maybe one or two other things). They have enough wounds that they can run around the field absorbing your opponent's firepower and still have the punch kill stuff.

I've never combat squaded my Terminators, because there is never a reason to. With grenades, they are one of the best anvil/hammer units in the game for their cost. There's rarely a reason to give all that up just so you can spread out a bit more and shoot your psycannons at different targets. Unless you're playing, say, IG or a similar army with no CC punch.


And you take Crowe for Purifiers as troops. Crowe isn't actually very good in CC by Grey Knight standards, and you can get much better counter charge type units elsewhere. You can use him as a counter charge unit, but that's not a reason to take him.