Honestly speaking the adjustment is just wrong if you look at those points.
It did not make much sense for a party to take a whole part of the ultimate/chef skill set (the core buffs which is arguably the most important part of the skill set) without these classes being present inside the actual dungeon.
Yes that's sadly right
Many players who mained buffing classes complained that they were useless due to everyone leveling up their own personal private buffer
This still won't change people will still take their own personal buffer. It's still better than taking a random buffer who will just be afk in the whole dungeon like your own personal buffer.
This was to help encourage a more different variety of classes within parties to be formed instead of the generic shadow knight, poko, dende, karma + extra standard party.
Now the party will look like sk, poko, dende, karma, ultimate. This just created a fixed party not a different variety of classes within parties. As long as crit dmg is not a thing this party won't change.
My problem with this change is just it does not fix anything. It just forces people to take an ultimate with them but this ultimate will still be a friend or a private buffer. I know we have the problem that buffers won't find a party but that's sadly how dbo designed buffer they have no dmg and are only a support class. So they are literally useless in runs where you just want to spam something.