One thing that really helped limit potential abuse in my campaign was switching from "Add the levels" saves for multiclasses to the "X levels of Fort good plus Y levels of Fort Poor for an (X+Y) level character" system. Basically, in my campaign, a Monk1/Paladin1/Fighter1 would have the same base Fort Save as a Fighter3 -- three levels of Fort Good.
In this system, it still benefits you to take a level of something with good saves, but you don't get the illogical stacking that lets a third level character have a +6 base save.
-Tacky
In this system, it still benefits you to take a level of something with good saves, but you don't get the illogical stacking that lets a third level character have a +6 base save.
-Tacky
