Given that some trees do use the stat-not just the obvious ones, but strange ones like Summoners using it to up the durability on pets-it would in fact be a fairly bad idea to remove directly.
I'm not saying it doesn't need work. The issue is, I've seen such incredibly variable views on how much work that it needs when requesting feedback. I have no idea how much work it needs, and half the time suggested boosts for it equate to straight, and often massive, buffs.
To me, there's multiple issues with that. The obvious one of either powercreeping the player or enemies is there, but there's also a huge one, where that could make players feel like Constitution is a god stat.
Players will, very often, do anything possible to raise durability in a simple way, in a Roguelike. Complicated durability tricks tend to end up more effective and less used, but simple and strong durability tricks tend to end up the abused ones. So tons of people will start picking up tons of Constitution if it ends up really, really effective.
Making Constitution feel essential to people will cause huge backlash against other parts of the system-namely against any class that runs three stats. Considering how much of a problem MAD was for the few classes that ran four stats-and how many classes run three stats-this strikes me as a developmental nightmare.
So straight up buffing Constitution much at all has repercussions that are, to me, seriously undesirable. That's why I basically said I don't see any real good in making it a "core" stat that people want to buff a ton-because, basically, people instantly will.
(A small buff would
hopefully avoid that. Emphasis on hopefully.)
Honestly, I think how much it bothers people that there's a defensive stat, and that it's not very good, tends to back up my opinion on that.
Optimally, I'd really like to just make Con buff, say, physical power, so it just sidesteps this and is no longer pure defensive, but I'm totally hazy on how to go about it precisely, without being another form of power creep. How much physical power would it take, and how would you make it have parity with, say, Magic?
(I did have this idea; Make Willpower grant 0.7/0.4 Mind/Magic Power, Cunning grant 0.7 Mindpower, Con grant 0.4 Physical power, and Defense grant 1 Defense/1 Accuracy. It's a bit of power creep in all of those directions, but it does create some interesting boosts to weaker statistics.
Having said that, the test group I suggested it to disliked it. Another possibility I considered was to change Magic to "Discipline", have it grant 0.4 Mindpower, and lower Willpower's to 0.6, then do the rest-the test group hated that it buffed Mindpower classes statistically, when they already largely just need two stats-but I disliked the amount of careful find/replace I'd have to do to code it.

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