I was using my Daiwa underspin US40XD yesterday and noticed it took a lot of winding to get the lure in so I looked it up and was shocked to find it had a 16" ipt. This reel is on my ultra light, which I don't use much. I might go out crappie fishing with a neighbor and was wondering if that low of an IPT would be ok?

That's all it's any good for , so use it.

That's pretty much the standard retrieve rate for underspin and spincast reels in that size. My little BPS underspin (rebadged Pflueger 4410UX) has the same retrieve rate, and it works fine for tiny jigs, Bitsy Minnows, Beetle Spins, and worm/bobber fishing.