Just got the game and I didn't realized that he used to cost 3 resources. Yikes! Compare that to the Fornost Avenger, which is 3 cost 3 4 (with Surge to boot). 3 cost for Fornost Bowman would have been way too slow.

Now that it's at 2 resources, he seems much more manageable and in line with other 2 cost 2 4 Ranged allies (with just a little bit of setup). I'd typically summon him when there is a guaranteed kill on the board, preferably once all enemy actions are spent to keep him damage free. He doesn't have any , which is completely fine since an ally with 4 and Ranged should always be attacking.

I have tried this ally a couple of times. He is not as bad as he seems. If you are able to reach 4 , then you will not have any problems with enemies and you can one shot many smaller minions (in single mode). Ranged keyword is nice bonus, which can be used to vanquish some flying bats.

He is quite expensive and that is the reason why we do not see him so often. But one copy for some specific scenarios could be good choice.