Which is better: An arbitrary heavy handed system which reduces early game economies across the board
It's hardly arbitrary or heavy handed. It represents that you can only administrate so much at a time. It also represents that administration has costs associated with it.
Other than that power balloons significantly as you expand without any real cost except for the initial investment and the initial rebellion cost. In reality, part of the problem of maintaining large empires have been that those things are expensive as hell to administrate.
places artificial limits on expansion
It does no such thing. It simply makes you get diminishing returns if you expand beyond what you can adequately administrate.
or that makes you make more clicks
I don't mind more clicks, especially since it's not something I'll be clicking every five minutes in the game.
Modifications to provinces far away (distance) in economy and autonomy.
Part of the whole reason that the mechanic was introduced in the first place was precisely because of how wonky and hard to balance overseas and long distance territories were. This simplifies the system greatly.
Modifications to autonomy/economy based upon # of provinces. Modifications to provinces far away (distance) in economy and autonomy. Both of those could be mitigated some by technology - Administration/diplomacy levels giving the player a direct way to combat a given inefficiency.
So...exactly the same system that there is now except that you are introducing a far more complex system in place to achieve the same amount of balance? I like the simpler system that is in place now, thank you very much.
Not to mention that that would be significantly more resource intensive while yielding no real benefit.
A player who plays worse than another player 'is outplayed' won't see that difference fully expressed in the game because the better player is severely handicapped.
Except that isn't even remotely true. Nothing is stopping you from taking 100% OE peace deals. It just means that you'll then have to find a way to compensate for the added corruption. It's another strategic factor to consider and which you must make plans around. In an individual war this has virtually no change on the actual game. It only matters in the sense of the greater strategic picture where you must consider factors beyond the war.
The better playing player is by no means handicapped. Also, that wouldn't be a handicap regardless, since it applies equally to both players. The worse player has no advantage over the better player since they are both subject to the exact same conditions and rules.
In any case your arguments are pointless, all corruption does in practice as a mechanic that exists in a strategic video game and not a simulator
or real life
A strategic simulator based on real life and with many aspects of it shaped by real life. Stop pretending that EUIV is somehow not at all historical. Yes, it's a sandbox, but it's a
historical sandbox, which is why stuff like history and historical context and plausibility matters. It might not take primacy, but to state that one can simply dismiss it out of hand is also to completely ignore what the game is.
is make the player sit around and do basically nothing, make no progress for large portions of the game,
Except that's just demonstrably false. It doesn't allow you to continuously take high OE peace deals, especially if there are other mitigating factors to consider (e.g. low Religious Unity) in war after war after war.
Absolutely nothing is stopping you from going to war and having war after war after war. You can still take land in war after war after war. You just have to have some self control and not try to grab everything every time or else you face consequences, because actions have consequences. If you go crazy expanding then you'll have to take some time sitting down and consolidating your realm like nations actually had to do in reality. Conversely, if you try to constantly stay at war and take smaller peaces then your realm will be more intrinsically stable and thus having to sit back and let it stabilize won't be as big an issue.
particularly and specifically outside Europe where you can expect to spend an inordinate amount of time on speed 5 and you are punished merely for existing.
Yes, it's a problem for ROTW. And yes, it needs to be modified for that.
Any reform to mechanic such as the one already proposed by Johan will merely change the amount of time you have to do nothing, it will do nothing to provide alternative activities or make the game more fun.
It doesn't need to. The game is plenty fun as is and absolutely nothing has been added to make you have to wait that much longer except for under very specific circumstances.