Yeah, I try not to talk about Pikachu too much. It's complicated. There's a lot of misinformation and it's difficult to clear up, so I usually don't bother. I try to be unbiased about it, but people often give my word less weight because I main Pikachu. Also, I feel kinda uncertain about where he will end up, especially since my work is going to play a role in what happens in the future too.
The way the competitive impressions thread talks about him sometimes, they make Pikachu sound like a bottom 5 character, lol.
Anyways, the 10-20 range seems right to me. From what I've studied with Pikachu, I feel that the potential to rise higher is there, but the results can't back up those claims. Ryu and Pikachu are in the same boat in that they're difficult to play at a high level and because of that, they have a small playerbase. An additional problem for Pikachu is that he's light. So if you mess up, punishes are much more devastating. If you watched ESAM's match against Marrs yesterday, you'll see that he missed a QAC and got hit pretty hard for all the momentum he lost. Thus, that's another thing that hinders him. I know people mention killing as an issue too, but it's not as bad as the aforementioned issues. I mean, he's got a lot of situational setups and Up Throw to RAR Thunder can be guaranteed if you don't mess up the inputs (there's Stumbling Block #1) and you get the DI read (there's Stumbling Block #4). Still, as long as ESAM plays Pikachu, he'll always have a presence at majors. ESAM doesn't practice as much as he should (though I can't blame him for wanting to have a life outside of Smash), and he's kinda impatient (he was doing really well against Ally in the last match of their set, but he made a hasty decision in going for an Up Smash read), but I'm glad we at least have a rep. In relation to what I wrote in the CCI thread, I feel that both ESAM and other Pikachu mains could benefit from having an easy way to communicate and spread information/tips among one another (he was offered to join the Pikachu Discord Chat recently, but he decided not to).