3.5e's quadratic wizard quickly outpaces mundane characters in power as buff spells stack up in later levels. 5e seems to have addressed that aspect of magic power creep with concentration.
How would you apply concentration, or what examples are there of applying concentration, to a 3.5e game?
Primarily interested in solutions that are mechanical.
There certainly aren’t any official discussions of this. Wizards of the Coast has no interest in continuing to support older editions of D&D (they recently deleted all older content from their website), and definitely hasn’t discussed 5e content brought back two entire editions.
Moreover, I don’t really think any “guidelines” are possible. What you really have to do is go through every spell in the game, one-by-one, and decide if concentration makes sense for it. Compare with 5e, I guess—if 5e has the spell, use that, if not, try to find something similar and go off of that. Done well, it might well improve balance, but it will be extremely difficult to do well. No one is going to be able to produce any short list of parameters for which spells get concentration and which don’t, there’s always going to be exceptions (or, at least, making numerous exceptions will be necessary to achieve balance improvements).
And even if you do it, it probably won’t change the reality of linear warriors, quadratic spellcasters. Doing that requires more thorough adjustments to each and every spell than just adding concentration. After all, if nothing else, a mailman build doesn’t suffer from concentration being put on things at all, because everything a mailman does is instantaneous anyway—and that build is plenty broken.
