That's exactly why people go with the magic item idea- most magic items are very minor improvements of that sort. eg. +1A for one of the stands, or a re-roll to-hit for one of the stands.
Fore the more fancy Elite units you can look at the banners- +1 save, +1A, etc. (though they all have drawbacks).
The points of magic items are generally slightly higher than they should be, so people won't complain that you've made something broken in the game.
There are 2 main downsides to magic items though:
1) Prices are set, regardless of the unit they're attached to. Eg. The +1 save banner costs the same for a unit of Chaos Knights as it does for a unit of Night Goblins, even though it's far more useful on the Knights.
2) There are no magic items that affect shooting. Still, I'm sure most opponents would agree to let you take a combat magic item and apply its rules to a shooting attack.