@Razh:
I'd argue he needs more variety too. Just compare him to the other two from trio and you'll realize how lacking he is, in range most of all.
Anyway, learning stronger moves doesn't mean you can't learn weaker moves with more range as well. It's like if Zoro gave up from aerial slashes because physical slashes were stronger, or something. And let's not forget Lucci was able to cut steel with his Rankyaku Gaichou. And, like I mentioned before, Burgess elbows holes in the wall from a big distance.
I don't know, gaining more range seems like a natural progression for someone like Sanji. He's already able to stay in the air by kicking it, kicking the air to cause damage in the distance can't be that far off.
There are only so many ways in which his attacking power can go.
So what if he lacks range? That was never considered a weakness in-universe. No one has ever told Sanji that his lack of reach is something that needs to be worked on.
And if you're going to pull the RPG stat card, then do not ignore that Sanji has far more mobility than the rest of the trio, compensating for any range issues.
I mean, next we're going to say that Nami and Usopp need to be physically stronger, or that Franky requires more speed. Again, it would be nice if they did, but it's not what they need.