It has potential but probably isn't going to work very well in OU. It's unexpected, and Kedleo packs some fantastic physical moves like Close Combat and Aqua Jet, but it lacks fire power. Base 72 Attack is far, far below OU standards; Breloom, Conkeldurr, and the other Fighting types of the tier laugh in the face of that. Even if Keldeo has a Swords Dance boost up, it still only reaches 534 Attack. This may seem appealing, but if I gave the same boost to Breloom it'd reach almost 800, so there is a huge gap in power. There are things that can quite easily take a +2 attack from Keldeo and kill it back. 534 is also assuming you're using Adamant, which isn't really the best idea when Keldeo requires Speed, so Jolly is generally better. This means its Attack it even lower. It's also assuming you get the attack boost in the first place, because if you don't you're stuck with this terrible 267 Attack stat that won't touch any walls and will miss crucial KOs that special Keldeo would get.
The only thing physical Keldeo has over Azumarill, Conkeldurr, Breloom, Mega Medicham, etc. is speed, but all of those Pokemon carry priority and a much better Attack stat. So really it's just plain outclassed.
Some calcs:
>-1 252+ Atk Keldeo Aqua Jet vs. 252 HP / 252+ Def Landorus-T: 50-62 (13 - 16.2%) -- possibly the worst move ever
252+ Atk Keldeo Aqua Jet vs. 244 HP / 0 Def Gliscor: 84-98 (23.8 - 27.8%) -- possible 6HKO after Poison Heal
252+ Atk Keldeo Close Combat vs. 228 HP / 0 Def Azumarill: 88-104 (22.1 - 26.1%) -- 6.6% chance to 4HKO
252+ Atk Keldeo Aqua Jet vs. 0 HP / 0+ Def Sylveon: 64-76 (19.3 - 22.9%) -- possible 6HKO after Leftovers recovery
