I'm still using it because old.reddit.com still works, and until it doesn't, I probably will. That said, I'd rather the fediverse thrive than the increasingly corporate-beholden reddit does, so I'll favour what sparse engagement I make to a lemmy instance first.

I think what's hardest to replace from reddit is the absolutely monstrous archive of posts and discussions, which seems to be a bit of a two-edged sword for them (if the official statements are to be believed) - it costs a tonne in hosting, but makes them the most relevant source for real human discourse. This needs to be handled better, and ideally I'd want to see:

• Some sort of archive.reddit.com. Minimal, flat html, ideally anonymised as much as computer-ly possible to help with the inevitable privacy issues this would raise.
• Some sort of mobile.old.reddit.com, as they seem incapable of making an app without bloaty (both visual and bandwidth wise) "features". Call me a boomer, but if I can do something without a specific app, I would rather do it that way.
• Separate i.reddit.com and v.reddit.com into different companies from the main reddit, reddit should be link aggregation and discussion, content hosting seems like a costly thing to try and monopolise.
• If it really costs so much to run the APIs, I'd rather see more user-based rate limiting than price gouging to discourage bad actors. I do not think that is why they are price gouging, but am trying to assume good faith on their part for discussions' sake.

I know I'm an idiot, and some of these are possibly already done and I just haven't looked hard enough, probably some are impossible for obvious reasons I haven't seen. Though even if reddit as a company turned around and tried to become a curator of the discussions it holds rather than milk it's current audience dry with ads, I'd still rather see lemmy out-compete it. Protocol > Platform.