Warrior General Games

A lot of people say they're all very important for safeties, so would a good build have them all soft-capped and pretty close to each other?

Learn to spell throughout you n00b... other than that seems solid for a balanced S.

Balanced - Speed/Agil/Vision/Strength/Tackling Even

Coverage - Speed/Agil/Vision higher

Run Stuffer - Agil/Strength/Tackling higher

Yes, IMO that's a pretty good approach. It partially depends upon what kind of defensive system your team runs and therefore what kind of expectations are put on your FS. If your team runs a lot of sets where you are up on the line of scrimmage in nickel situations covering a WR 1-on-1, then speed and agility are your top priorities, with a fair amount of jumping also (and a pretty high vision of course). Whereas if your team tends to keep you back in "center field" and put a 3rd CB on the field in nickel packages, then (IMO) vision becomes your #1 stat with speed and agility both a very close 2nd.

Note everything I said above is for FS's. SS's are rarely (perhaps never) going to be matched up 1-on-1 on a WR, though they frequently are covering TE's or HB's. SS's also typically have a lot more run-stuffing responsibilities (again, depending upon the way your team plays D) so in those cases, strength and tackling become quite important.