Half as much? Sure. Close to as much? No, not likely. Oda just needs to actually care for him and make him stand out this arc if he's actually the silhouetted man and/or the man marked by flames. I'd imagine he serves a somewhat different purpose to Rayleigh if he's actually awaiting the crew and such. If he's not even that guy then there's no hope. Rayleigh was something else when he was introduced and with his later appearances, Gaban would be lucky to be treated like a legend, be strong and be important but if he's integral to the crew's journey to getting closer to the One Piece then for sure, he'll be hype. If he does play a big role for them it'd mean his contribution would be distinct from but still important like Rayleigh's since Rayleigh took Luffy under his wing and such, while Gaban would be giving them some very sought after help considering Kid and Law's words/implications.