Alongside the legitimate concerns echoed in your post, there has also been a fair bit of lecturing from techies joining the fediverse about how dumb Mastodon is for not having introduced Twitter-style discovery mechanisms early, and how that's the reason it's never going to amount to anything, etc.
IMO those arguments are largely misplaced. Yes, discovery tools (including the ones Mastodon already has) can be powerful, but we also need to carefully reason about their effects.