Yes, I've said from the start that I'm well aware Buggy is no powerhouse, and I highly doubt that he'll magically power up to a Yonkou-level opponent by the end of the series. However, I do believe his DF power has the potential to be used in a highly creative fashion, and I said in the past that I suspected that he's able to manipulate Haki to some degree (his bombs). But otherwise, I wouldn't expect to see him beat guys like Mihawk in a straight-up fight.
....However, regardless of his strength (or lack thereof), I still expect to see him rise to the top of the pirate world!
Maybe Ace can become his toady once Whitebeard bites the big one.