
He's not a very good piety farm, either, except in the rare case where you want to immediately convert a bunch of glyphs then convert out, and have no plans to worship GG, JJ, or Mystera. Otherwise, the optimal strategy is to wait until I've converted to my preferred deity and then start killin' stuff, because that's going to get you piety with your 'real' god (TT, Dracul, and JJ all give piety for kills, GG for the piety on level-up). Binlor and Mystera are much, much better piety farms, and IMO in a vicious dungeon GG is the best counterpart to Pactmaker due to the ridiculous amounts of piety you'll eventually get from leveling up (unless you've prepped him).
Every other deity is either flexible by default (like JJ) or at least has something you can do with them apart from their speciality (like EM, who is primarily useful for her utterly broken Plantation+Clearance combo, but her other boons aren't terrible). And I do think the Taurog-worshipper is unique in being so completely inflexible: the Monk can in fact get magic resistance, and in fact his other class features (higher max res, double regen) make him very formidable once he does so; the Assassin has plenty of options even when poison isn't effective (mainly due to Swift Hands - now, if Swift Hands also didn't work against undead then you'd have a very good point), and TT has plenty of uses other than his poison boon. But worship Taurog in, say, the Slime Pit or Namtar's Lair, and it seems to me that you're deliberately crippling yourself.
I don't necessarily want Taurog to be stronger, but it would be much appreciated if something were done to make him more flexible, at least for high-end play. Otherwise we may as well put a veto slot at the church so that you can ban his altar as soon as it becomes more trouble than it's worth.