hm. Claw sharpen doesn't seem that useful. With only +1 attack and no speed boost, you're still gonna get run over by scarfers. Plus low accuracy moves aren't that good to begin with... (100 bp Iron Tail, 100 bp Dragon rush, etc)
Yeah, in theory I'm not feeling the utility either. It can't be used with any Choice item. Could be used with a Life Orb, but if you want outright power you're probably going with Swords Dance or Dragon Dance every time, at least one of which is learned by just about everything I can think of that would possibly learn a move called Claw Sharpen.
I said earlier that maybe there could be something like a Tyranitar with Blizzard or Thunder working out to pound Gliscor/Hippowdon/Vaporeon/whatever, but the more I think about it I'm not even sure that's viable when it could be boosting Speed instead.
I'm thinking the move will actually be mostly used (if it's used at all) by defensive or support Pokemon who want really accurate Sleep Powder or the like. Start with Claw Sharpen, then add a mix of status moves (Stun Spore, Glare, Will-O-Wisp, Toxic, etc.), strong attacks with dodgy accuracy but interesting side effects (Zap Cannon, Gunk Shot, Dynamicpunch, Magma Storm, Thunder), and support moves (Reflect, Light Screen, Aromatherapy, Stealth Rock, etc.).
Whether any of it will work in practice, I'm not sure--depends on too many unknown factors. But on its face, at least it's a way to get better accuracy on status moves without needing to drop Leftovers.