Whoa.
Mystera and Taurog don't benefit their niches?
I think, well I don't really think it - I sort of feel like I "know" it, that what you're struggling with is not a problem with Taurog or Mystera, but rather 3 separate cases of unintuitive weirdness with the fighter, the priest and the wizard.
1) Wizard doesn't need any help. That's the thing - Mystera boosts Sorcerors, Bloodmages, Fighters, Warlords, heck, even Berserkers, more than she boosts the Wizard. But that's the case of the Wizard being too good at what he does and overlap between his price reduction and mystic balance, rather than her not being as good in her niche - she's the best in her niche. I prep her for a string of weakenings even with wizards and I don't think I'd pick anyone else if the boss I was going to fight had magic resistance. But wizards benefit from EM and Binlor more, because they're so good at spellcasting that they don't need her.
2) Fighters are way better when played as spellcasters than if played in almost any other way. Warlords ARE spellcasters. And within the niche they belong in mechanicaly (spellcasters) they have plenty of benefits from Mystera. Fighters in particular benefit from her more than any pretty much any other god except Tikki Tooki. And neither Fighters or Warlords have sinergy with Taurog, not because Taurog's bad at boosting "warriors" but because they aren't in fact warriors. You couldn't make a "warrior god" that would benefit or synergize with them them more than Mystera, EM or JJ would.
3) Taurog isn't bad at boosting warrior types, in fact that's all he is good for. But the really niche warrior types in this game are in fact The Priest, The Monk and The Berserker. And while the Berserker can benefit from Taurog by going full retard niche, he's good enough at being a warrior that he tends to be looking elsewhere o shore up his weaknesses much like the wizard tends to not need any more spellcasting help from mystera.
As for the god preps - they're ment to be scumming-reduction mechanisms, and they are the strongest preps in the game if you know which strat you're going for. Having the altar you want right at the start lets you start gaining piety right away and guarantees you'll have the boons that have the most sinergy with your class-race combo. As for perp punishments:
Drac - you generally wouldn't want to pick him up early anyway, and his penalty is less of a problem than that.
Tikki Tooki - would be various kinds of broken if you could casually prep him anywhere you go. He's the only one with a really ridiculous prep penalty, but that's kind of justified, and you can still make him work.
Mystera - what prep penalty? She hands out piety for casting spells, and provides benefits to guys casting spells, and offers really strong boons to those guys. This is tied with the EM and Binlor preps as the strongest overall prep in the game.
Taurog - what prep penalty? I prep him for warmongers regularly.
GG - what prep penalty? I tend to prep him for any warmonger, or even when I just want a piety farm that doesn't require me to do anything but level up and convert stuff...
Binlor - what prep penalty? Prepping him = prepping a pissorff glyph (only way to do it), guarantees that you'll dismantle most cramped maps, provides +40% knocback and +30% on wall destruction eventually, and as much magic resists as you put an effort in acqiring. Also a string of stonesking which you can kill a boss with easily. It's probably the most broken prep in the game in any category, but it has to be there otherwise people would simply scumm for him.
EM - what prep penalty? Guaranteed slow on any monster, guaranteed IMAWAL for XP catapulting, piety comming out of your ears if you want to convert, and provides more plants per boon for clearance abuse. If you only grab the free glyph, entagle everythign and use a clearance, you can get to 50 piety just off IMAWAL, convert to whoever, desecrate her altar and drink a burn salve for 30 piety + 3 indulgences with the next guy. And once you locker avatar's codex, entanglement + clearance spam with it is one of the strongest prep-heavy strats on the game.
JJ - what prep penalty? Really, you only really want to prep him with warlords, and they don't mind. And if you wanted him in any other circumstance, having him available from the start would balance out any penalty he might give.
So in essence, the only guy with a serious penalty is TT, Drac isn't too good if you pick him up early (except with halflings) and JJ simply isn't too good. GG and Taurog can and should be prepped on most warmongers, and GG can be prepped every game if you just want an effortless 50 piety + humility. Mystera can be prepped any game if you want to win the game by using her boons OR if you just want a few points of mana and free piety, EM is better prepped than found and can be prepped anywhere for free piety AND benefits AND can win you games on her own, and Binlor is flat out broken.
Hope all this didn't come out wrong.
