"Siloing" is a design term for sectioning off powers or points to be used for a subset of things - thereby limiting how much min-maxing can happen. Usually in point build games, the problem is that people pour ALL of their points into combat and ignore everything else.
The simple house rule is to silo the points:
"You can spend 100 pts on attributes and combat skills, 50 on social skills and 50 on non-combat skills" or something similar.
I usually lump attributes with combat skills since they tend to overlap greatly, although you might do something like go "80 pts between combat skills, Strength and Dex stats, 60 points on social skills and Will, etc." and section off the stats with their skill types.
It's also important to look for skills or powers that are actually crossovers - "Intimidate" might be a social skill, but it really probably belongs in combat. Magic skills might be "mental" but you should probably drop those into combat as well. This prevents folks from doing workarounds to play the same min max game.
In point build games, I HIGHLY recommend limiting some skills/powers as unavailable, limited to a certain maximum rank, or only available as a package - "Sure you can get Super Ninja Fighting Style, but you also have to get Secret Ninja Lore Skill, Alliance with the Ninjas Background, and Oath of the Ninja".
I also highly suggest limiting disadvantages, since in most point build games those become the cheap out to getting extra points. Options include:
- "You can only take X amount of disadvantages" (still open to abuse)
- "You can only take a single disadvantage. Just one."
- "You can take up to X amount of disadvantages - but I get to pick which ones after you tell me how many points you want. I will choose viciously."
- "You can take from this list of approved disadvantages"
Wow this seems like a LOT of work
Yep. The problem is that most rpgs put combat as a regular thing, and even players who aren't combat junkies don't want their characters to die, so they usually load up on combat stats as well.
Once play starts, it becomes a vicious cycle- the characters are good at combat, so they tend to lean towards resolving things with combat, as a GM, you want to challenge them at what they're good at, so you throw combat their way. Since combat is happening a lot, they put more points into combat...
You can silo out XP and advancement the same way, or give only or give more XP for non-combat solutions.
You can see that if you take the houseruling far enough in the other direction, you basically end up with "Build your own class system", but generally a solid amount of siloing/package builds/limiting or forbidding certain options can do the job. The more options the game system has, though, the more painful this process is.