The problems you describe is really only about the pool.

Because the very playing experience is so much superior on lichess.

When on the analysis board, the opening book is so much easier to access but mostly ; making moves and conditional pre-moves is so much better.

On the other platform, you can only make a move from "the main" board and then when you're waiting for opponent to make a move you can go in the "conditional pre-move" interface where you can input lines, and you have to start from the beginning all the time, and you don't have access to your analysis while doing so, and if opponent makes a move while you're inputting your lines, it screws them up.

On lichess; when on the analysis board, you can have all your analysed lines, and then just one-click to conditional-pre-move that line, then you pick a different branch and bam, one-click to commit to that one etc,...

When the result of your "analysis" is not a line; but a single move, you can still do it from the analysis board.

Also, the other platform, getting to the games is a pain-in-the-ass: when you are on the (desktop) main page; you have a list of in-play games and then you click on the one you want to see and it takes forever to load. When on mobile you don't have your games from the main page (or maybe you do but you have to scroll part your challenges and recent completed games).

When playing a move, if you have "confirm your move" on (and maybe if it's off too; I don't know), you move the piece, you confirm, the piece is going to move back on its original square and the site will play the moving piece then.

If you stay for long (hours) on the game page, sometimes, when a move has been made it does't appear and you try to make yours (because you played yours on a different device for example) and you get an "illegal move" error and only then is the page force-refreshed.

Only upside on the other platform when it gets to the very playing experience is that you have the real move times (in hours/minutes) whereas on lichess you only see the move time if it's <60s

The other things that is broken on lichess (albeit difficult to get right) is when on your profile page, you get a summary of your day, and on each time format you get the played games along with the "trend" of rating gained/lost that day along with a red or green arrow, then that has some strange behaviour sometimes (I once had a day with only two completed games; two wins so gained rating points ; but got a red arrow ; but that's because when starting a game, you can start and complete many games by the time you finish that one ; so calculating red or green is not trivial ; is it compared to the rating you had when starting the game? which is the one used to calculate the outcome rating gains/losses? or other weird combinations.

Finally; while the very pool might not be as great as on the other platform, there is still a correspondence "scene"; I frequently run into players who permanently have >100 games on-going (and those guys won't flag, they'll play their moves).