My experience with using small base dies for AR-15 ammunition is the case fails for some other reason, or I lose it before the body fails from small base sizing.
But that's just seeing the glass half full.
OTOH, one could simply toss cases that would otherwise need a small base die to fix. I use the case gauge to measure my pickup brass before sizing, and I toss the ones that don't pass. (My own fired brass always passes a case gauge). The cases that pass pre-sizing are going to pass after sizing. The ones that don't fit might pass after sizing or they might not, but I wouldn't know, because they are already in the garbage. Those cases are going to be prone to case head separation and borderline sizing anyhow. 95% of my randomly acquired cases will pass a case gauge before sizing. There are a few that are obviously too long, and they are damaged goods, perhaps having been fired out of a machine gun of some kind, or out of a gun with grossly out of spec headspace.
I know some folks' guns have such tight chambers that they might need a small base die. But to me, it's pretty dumb to buy a gun with a tight match chamber, and then need a special undersize die to make ammo for it. Doesn't that just put you back where you started?
The point was to have a tighter fit, and then you turn around and make your ammo even smaller, so it's loose again? I haven't, to date, come across a case that is too fat to chamber, but then I don't have a wilde or 223 or match chamber in my rifles. Too long is covered by the case gauge. Saying you ought to get an undersized die, regardless, is akin to suggesting you ought to have your chambers reamed out to be oversized, just so that you can be assured of being able to shoot sloppy seconds damaged brass.