I miss the stuff that got squashed by big companies or DMCA or whatever, and that falls under my first bucket, but my two main problems with the internet now vs the internet 15 years ago:

1. Content: The vast majority of content is consolidated on just a small handful of heavily-astroturfed platforms. There are obvious problems with a half dozen or so private companies getting to control who sees what and what is or isn't allowed. Beyond the implications about being able to spread leftist propaganda or express dissent about the owners of said platforms, There are so many content creators these days making good forward-thinking content that got their start making content on some corner of the internet that doesn't exist anymore, or at least not at the same level, and there's the question of what sort of art and ideas we're missing out on because they're trying to get their start on a platform that's actively trying to suppress them. (I'm thinking specifically about the way that tik tok deprioritizes content from people who aren't attractive and wealthy-looking, but it's easy to make a case for any of the other major platforms doing the same thing.)

2. Privacy: When you visit a webpage, everything about you is recorded, your browser is fingerprinted, and a profile is built around you. Even if you don't ever interact with a service they can build a profile about you based on other people who have your phone number in their contacts, your email in their send history, etc. Thanks to smartphones, these companies have data on where you live, work, visit, when you sleep, when you're out of the house, how big your house is, where your bedroom is, etc. Right now, as far as we know, they're just using and selling that information for ad revenue, but the other implications - especially as we descend further and further into fascism - are terrifying.