What distinguishes it now from the previous format is only the appearance and number of matches, because previously the participating clubs were put into several containers (groups) but now they are all united in one place even though not all meet each other and the other difference is only the number of matches is much more than before. Apart from that, everything remains the same where they have to compete in 2 legs and must try their best to qualify for the last 16.
Interesting and not all depends on comfort but I personally actually like this new rule if UEFA provides an event that is not too close to other competitions. currently there are many matches that we will see of course this is very good but on the other hand I hope the organizers do not force it too much with a tight schedule because the important competition is not only the Champions League.
I feel like the new system will make sure that we are dealing with more games, but also less chances for lower teams. It mean that, since we have more places, there will be some more smaller clubs which is always great and they would be making a good chunk of money for being in the groups, but they are just teams for bigger clubs to beat at this point, I do not think that it will be anything more.
I understand that we are going to see this situation changing overtime, and those lower teams may try to be better, but I doubt it will happen. Teams like Madrid, City, Bayern, PSG, Inter and so forth will keep on being ahead of everyone else, and that's why they are just making more money this way by beating more teams that's it.
When talking about the chances of low clubs, it's actually the same regardless of whether it's a new format or an old format, because we are certainly aware of all the situations that are happening right now, the chances of a club that is indeed smaller in the Champions League, they just have to be able to make some differences from the matches they play.
Let's take last season's example where Real Sociedad and Copenhagen qualified for the last 16 due to several things including the opponents they faced not playing well (especially for Copenhagen).
From the perspective of the beginning of last season, Copenhagen was the club that had the smallest chance in Group A because there were Bayern and Manchester United, but the surprise happened when they were able to finish in 2nd place for the group phase.
In the current league phase, it's the same where the possibility of qualifying directly is clearly difficult, but for the play-offs they still allow it to depend on their performance on the field.