Depends how you implement it.
Sure, if you go all 3e on it and put DR everywhere except under the kitchen sink and with 97 different types and exceptions then sure, it's not going to work very well.
But if you add it in just in a few always-on situations you could potentially solve a few headaches all at once.
What if, say, instead of leather being AC 12 and studded being AC 13, leather stays at 12 but studded also becomes 12 but with DR 1. Ring then becomes 13, scale becomes 13 with DR 1; chain is 14, splint and banded pair up at 15 with one having DR 1, plate is 16 and field plate is 16 with DR 2...and so forth - net effect: lower the actual AC values of heavy armour (something I've wanted to do for ages).