Objectively? Now that's going to require some evidence.
For you to be able to say this rationally you'd need to come up with a set of metrics that accurately constrain anticipation of what happens in the game's peace conferences. Right now, it is possible to get nothing with over double the % contribution that in other cases lets you take entire nations worth of territory.
Also, because peace conferences are tethered to the trash algorithms for occupation + capitulation, they are necessarily tainted by those given how control of territory influences cost.
Speaking of objectivity, war contribution is a broken mechanic in the objective sense (bombing is bugged and you can 1000 bombing with only infantry), which also influences peace conferences. But all that aside, the conference itself has serious issues and I'm not convinced all of them are working properly (shadow puppeting and taking discount land held by other factions that would normally cost 10x more rather than less immediately come to mind)
Technically, I'm not the one that needs to provide evidence, I'm refuting someone else's claim.
And, no, while the peace conference and the algorithms are not up to your liking this does not prove nor mean they're not working. They're just not working for what you, or the others want. I am not denying that it could be improved, but it's not, by any means, broken. And no, ruining your fun doesn't mean the system is broken, it just means it ruined your fun.
For starters, you want the game to cater to you, while in reality, that's not what it meant to do. It's going to try to treat all the 'players' involved in the war fairly under the measures and algorithm it's using. Maybe you're asking for the computer to lay down and give you more leeway to win in single player? That seems more accurate to what you desire according to what all of you are requesting.
1) There isn't really anything wrong with the AI's logic at the peace conference table. It's playing optimally by selecting the most valuable provinces for itself and maximising its war participation usage. It's playing properly by the rules that its been set, and the fact that it's producing unsatisfactory results means that those rules are not fit for purpose.
2) I don't understand what you're saying here. None of the options I listed would be impossible in HoIIV or contrary to the design of the game. And the game doesn't really have an objective, it's a sandbox game where you can do what you want without defined win conditions.
3) It is 100% the fault of the system if I can't revert a mis-click easily. At the very, very least there should be a little "are you sure you want to do this" box popup that appears when I submit my demands, and I'd rather go to a system where selected treaty terms are only locked-in at the end.
4) The game can be difficult to understand but I wouldn't say most of it is un-intuitive. You build units, you ram those units into other units, they fight, different stats affect the fight, you win. The details of what the different stats do can be looked up in game. There are a handful of things that aren't properly-explained (trade influence and how to increase it, what infrastructure does, some details of the supply system), but the peace conference system has got to be one of the worst examples. And because of the lack of an "undo" functionality its very difficult for new players to experiment with it and work out how it works.
"The AI doesn't make a mess unless the player intervenes" is not good enough. The player is always intervening. That's the whole point of these games. Fun peace conference mechanics should be built around player intervention and should always produce a satisfying result.
1) You are wrong by any account of players that continue to enjoy the game. Most players are asking for a peace conference AI that will select gains and puppets in a aesthetically pleasing, logical-for-actual-people distribution of land that "won't cause bordergore". What the computer is doing now is not satisfying that desire.
2) Then you have ignored what the game presents in it's vanilla form. A results screen roughly at the start of 1948 or 1949. The span of a regular campaign of HoI.
The objective is, between 1936 to 1949, to grow your country and win for your ideology or your faction over the others. That you want to ignore this objective is fine, the game perfectly allows you to do that which is cool. BUT the game has clearl objectives for the players which is why the peace conferences give options that would, relatively speaking, help along in allowing you to fulfill them. The other options you are suggesting would be quite welcomed, like I said, but they don't exactly encompass what the game's objectives of the original vanilla game is.
3) If you made the mistake in the first place, that is actually still your fault, not the system. It would be nice for the UI and system to be updated a little, however. Yes, a simple request for comfirmation when pressing done or pass would do wonders, I agree.
4) I must point out that a lot of the games stats are actually still somewhat abstract and even good players are still trying to determine the how to best use and interpret them, despite the stats "telling you" what they "do". I agree that the UI and systems could be polished a bit more.
To your extra addendum, I'll just smack you with what I just said above: You want the game to cater to you, while in reality, that's not what it meant to do. It's going to try to treat all the 'players' involved in the war fairly under the measures and algorithm it's using, even if the other "players" are AI. Maybe you're asking for the computer to lay down and give you more leeway to win in single player? That seems more accurate to what you desire according to what all of you are requesting