Definitely not even remotely close to the most pressing issue with this game. Delpheus makes a bunch of threads about this every time a new DLC is on its way and nothing has changed.
Playing in the MP community, I've literally never heard anyone even mention peace conferences as far as needed game changes go. The reason is because when they happen, it is either when Japan curbstomps China and annexes everything with no other participants other than Manchukuo, or when the Co-Propsperity Sphere and Axis have been defeated, or when the Allies or Comintern have surrendered. Barring t he first situation, which is irrelevant because Japan will have all the warscore anyway, the other scenarios either mean the war is virtually over or literally over.
Peace conferences are only really a significant issue if you're playing a meme campaign and competing against great powers to try to snipe every bit of land you can. So it's interesting that on the one hand, we have people yelling about peace conferences, which are mostly only an issue in meme campaigns; but on the other, people complaining that there is too much emphasis on alternative history? Ah, the duality of man.
A working logistical system and improved AI there is frankly a much bigger game changer than any kind of tweak to peace conferences. Tired of having to use the console and tag over to delete my allies' armies because they keep squandering supply. Also tired of seeing the outcome of the war decided in the first few weeks of Barbarossa 4/5 times with good players on all sides because either the Soviets stop the Axis cold or get immediately encircled and annihilated with no possibility of a comeback. Done right, the new logistics and a rebalanced Soviet Union that is a bit weaker to compensate for the additional burdens on the Axis could be literally game changing and lead to a more fun, engaging, and realistic war.
Doctrines, planning bonus, and the battle planner are also in significant need of reworking. Peace conference fixes and improvements are definitely something that should be done, but in terms of its importance it's not only FAR from being the most important issue in the game, it's not even in the top three. Some people just like getting on their bully pulpit and making a lot of noise, but it's not nearly as pressing as some people like to present it.
As others have mentioned as well, Player Led Peace Conferences mod is a great workaround. The only issue with it is that as a demand, you cannot get co-belligerents to puppet or satellite tags. True, we need a real, official solution, but as a matter of priority the developers should focus on issues that can't be solved by modders, and this seems to be what they're doing to some extent. Whether we will see more changes with doctrines, battle planner, planning, etc remains to be seen, but the news with logistics is a hopeful sign.
Hopefully we will see a change in this DLC in respect to peace conferences, but I doubt it. Honestly, as a matter of priority, it's not worth focusing on at the expense of more significant issues so don't be surprised if nothing changes on this front.