I'm going to run with the arguments UEFA made for the new mode:
1. more teams = more participation for more nations
2. more teams = more matches = more money for every team
3. more excitement for the last matchday bc more rankings matter and not everything will already being decided on the 5th group stage day out of 6 group stages
4. the new seeding gives us more exciting matchdays bc big teams will face big teams at least twice
Lets look at these arguments and how they played out:
1. is already bullshit bc we have FIVE FUCKING GERMAN teams in the cup. And just look at the qualification process! Like what the fuck. It's a fucking mess. And where are all the new nations getting a shot? Yeah, right.
2. Ah yes, bc all the new shekels are going to be distributed fairely among the participating teams. Sure. And the sky is green and the sun is blue.
3. Personally this was UEFA's biggest selling point in
my books. Because some people really seem to have forgotten that most of the decisions where actually already done on the 5th group stage day and only minor decisions where left for the last matchday which rendered the last matchday pretty uninteresting and useless. It happened more often over the last decade than not.
Now let's have a look at table before the upcoming last matchday of the new mode:

The table on the Wikipedia page has this nice little feature with letters behind the teams and which options they have left.
- 12 teams will be eliminated at the end. 9 teams are already elminated so it's 3 spots left. Wow.
So much decisions left. 3 spots. But that Man City and/or P$G might getting kicked out is fucking awesome.
- At the top only two teams, Liverpool and Barcelona, are actually already qualified for the next round and don't have to go to the extra round.
Ok, cool.
- 16 teams, the blue teams, are playing for either moving on directly to next round, going to the extra round or being eliminated. 10 blue teams can actually still move on directly to the next round (starting with Aston Villa til Celtic). Plus Atalanta (7th) and Leverkusen (8th). That's not bad.
There is some action left and could get really dramatic in the end. So one hand I'm kind of excited to see it being played out but on the other side there I don't actually feel the excitement and drama. Probably bc the consequence of losing on the last matchday for any of these teams will only be seen in a few weeks after the extra qualifying round is done and we see which teams got kicked out.
4. Mixed big bag here. Yes, we saw some big clashes between big teams but did it really matter? Like how much matters Barca's 4:1 win against FC Bayern? The only big team match that had some impact was P$G vs Man City on the last matchday bc it didn't end up in a draw but in an actual loss for one the two teams and put it in some not favourable position (Man City). But besides that?
There were some real cool matches tho on every matchday but yeah, that was to be expected and is nothing just bc of the new mode so no point taken by the UEFA here.
But let me sperg a little bit more about one point I haven't touched yet: more matches.
It's not just more matches, it's acutally more-more matches. Bc we got more teams participating not only in Champions League but
also in Euro League and in Conference League. And in summer we are getting the club world cup - which got added more teams for more matches. And the next national team world cup got stocked up with teams.
I'm a Frankfurt Eintracht supporter, Frankfurt plays the Euro League, so naturally one day is resevered for watching Frankfurt matches.
My time is limited like everyone's else time. My day only has 24 hours and despite me being on the shelf for the last 3 months and probably the next 2-3 months more bc of an injury and op I had to undergo and thus being unable to work I still can't waste like 8 fucking hours a day or whatever just to watch football live and rewatch stuff and shit.
Nobody gives already a shit about the Conference League and now even less.
And the issue for the players of the top teams and top nations having match after match is obvious. Not going to touch on this point tho bc I'm already sperging way too much.
I ended up actually watching less matches. Because for 1. too many matches and 2. I'd have to throw money at more tv stations just to see them (Sky, DAZN and Amazon). Sure, pirating it is an option but as someone who is living in Germany I already have to throw 20 bucks every month at the public broadcasters of ARD and ZDF. If I don't I'll go to jail. It's not an option, it's a fucking must-buy. So I used their internet radio broadcast bc I already have to pay for it. No extra shekels from me, sorry not sorry UEFA, fuck you. And ngl it was way more fun bc you get the actual broadcast for the game with like 5 minutes before and 5 minutes after the match and literally no fucking ads in between. Fuck tv, I'm never going back.
I went with some optimism in the new CL mode. It's not completely killed yet but my tendency is more being against it. We will see after the extra qualification round.