Recover is the lynchpin for CAP 3's success in OU.
Every single major boosting move has been disallowed, and rightly so, and thus CAP 3 lacks a lot of either the staying power or sweeping power to actually be efficient and unique in the OU metagame compared to other similar Pokemon. Consider, for instance, that Arcanine is not an OU Pokemon, when Arcanine already boasts so many things that clearly set it miles and away above CAP 3! Arcanine packs 110 Atk, Close Combat, Wild Charge, Flare Blitz, ExtremeSpeed, Morning Sun, Intimidate, and Flash Fire. Arcanine is different from CAP 3 thanks to Dry Skin, but makes a very cogent case for the uphill struggle that SR-weak Fire-types face in OU. Recover on CAP 3 would give it a real means to overcome that vulnerability reliably, and thus come out ahead of the game and actually be a usable addition to OU. CAP 3 without Recover, I fear, will not be able to keep up with OU in a meaningful way.