I wonder! I have thought about it. I don't have the spec, but I'd take it on a full steel fighter. I tested and w/ cleric it seems like armor caps around 18. So even if you are wearing incis you are gonna get stupid nerfed regen. Now, if you go way up to steel... I got 70 mana on my Khurite. lol. I got vitalism and all that, switched up a lot. It gets decent regen at around 27% (before I had cleric,) and I'm all psy on my veela who also has 70 mana, and she has epic dogshit regen cuz no vital. Even that kinda fills up tho. 10->20% is gonna be a big deal. If I was a pro fighter I'd go full steel and spec hybrid with a Khur or a Kallard lol. Do the old 50 int meme. Seriously. You got enough points to do it now. You can build some pretty good chars and add onto that the ability to reflect yourself, lesser, purify... you could switch up and go full MO1 hybrid lol, but I dunno why you'd throw any hi mana spell other than MR. I think it would be a pretty strong contender for 'viable.'
My problem is that it's telegraphed hard that way, and the +50 points turns out to be a convenient amount when trying to hybridize magic, but not so much when trying to be more versatile in other ways.