Shard O'Glase said:
Considering that a 4th level spell can give some really cool racial abilities permanenty if randomly. (reincarnate) I really fail to see how a 9th level spell costing 5,000xp giving one racial ability permanenty but not randomly is out of line.
But still if people wont allow it like that would they allow a sort of modified contingency, when I die I wish to be reincarnated as a deep gnome. Eat the 5,000 xp, kill yourself lose a level and come back as a deep gnome in thier prime with SR 11+level and +4 dodge bonus,+2 to all saves and a few other abilties.
No can do thats like wishing for more levels, which cannot be done (ECL +3 for one wish). You also can't wish that the fighter come back as a Troll when he dies (ECL +11).
You also can't wish for the affore mentioned Girdle, because wish does have a limit on the power of the magic items it can create.
Wish is powerful, but it has its limits (which are described in the spell description). Anything not listed there or beyond the wishes power don't happen, happen badly, or happen partly.
If you wish for a Trolls regeneration there are a few possible results:
1) You get the ability for one day
2) You get polymorphed (as polymorph self) into a troll
3) You become a troll and lose 11 levels to balance out the ECL
In the case of regeneration and SR, I would not hesistate to "screw" over the players. They are trying to screw over my campaign by wishing for things obviously too powerful in hopes that it will work. The fairest way to handle anything that is a wish for a power thats too good is to turn the player into that race, and then take away their levels to compensate, or to Polymorph/Shapechange (leaning towards shapechange) them into it as the respective spells.
Don't even consider letting someone wish for natural SR without consequences. In the case originally noted the character would get SR 29. A Mantle of Spell Resistance gives SR 21, for 90,000 gp. Your giving them something much more powerful than even that. All the time. Would you let the player wish for a +3 or +4 Vorpal sword? Both effects would be on par with each other.
Also remember it takes one wish to boost a stat by 1 point. Do you see a +1 Str being equal to a SR of 29? I know I sure don't, and I don't think anyone else does either.
Look at what a single wish is capable of and then compare that to what the player wants. If what they want is better, odds are you need to limit/twist the wish.