Hey everyone,

I've got a long-standing site, I got on-board with SEO pretty early (we're talking 2005 :lol: ) - it ranks highly and, somehow, has done for a dozen years now.
The architecture of the site is pretty old though and has been layered over the years with what's likely some less-than-ideal PHP code. But it is pretty fast, responsive and mobile friendly to an extent (room for improvement, scores 70 odd percent on that front).
That's the front-end at least, page optimisation/coding on internal pages isn't great and many of the URLs are non-canonical, though my dev made an attempt to update some.

It's now at the stage of needing a bit of an overhaul, I thought maybe it'd be beneficial to move to a Wordpress platform but, given the excellent ranking, I'm also aware this might not be worth dicing with? I suppose ideally, I should leave all current structure and links in place where possible and maybe just keep face-lifting it and trying to improve code where possible?
My dev said canonicalizing would be a "big job" but isn't this just a case of making an index list of alternative SEO-friendly URL's and implanting the alternatives into the title headers?