Personally, I love ideas like stance changes. However, making them buy-able would be ridiculous. I shall now rant, you have been warned.
I have five points to make with this post:
1.This should be implemented as a variable system that could be used if the room allowed it, but on default would be switched off.
Basically, make it a server option. If people want to play with custom openers, allow it as a server option, sorta like checking sambo. This allows it to not impact those that would not want to use it or play in a more "fair" (which I disagree with) setting.
2. This should NOT cost anything for the players. This should be implemented free of charge, and allow for total customization of positions, to an extent. Unfortunately I don't know if it would be beyond the programming that Toribash uses, but allowing the players to have their own custom setups that they can choose from at the beginning of a match (almost like that mod that allows players to choose their opener from a list of ones they saved) with certain restrictions in place, ie, One foot must remain touching the floor, extremities cannot be more than x distance away from starting position, ect, depending on the mod.
3. This is totally fair. The hell are people talking about this being unfair? Actually, if it's restricted to presets, yea, I might see one position becoming dominant in certain mods, but if given total creative freedom that everyone else has the ability to use, you will see such a huge expanse of starting positions, each and every one bringing certain weaknesses to the table that can be exploited. think of he variety of claps we could see, the variety of kicks, the variety of anything that could be accomplished with this! It opens a whole new realm of possibility for countering the "metamoves" that everyone uses. Honestly I'm getting a bit tired of carrying people out of the ring in aikido, even more tired of suplexing. This adds another variable, making things even more complicated, making things even more fair in my eyes. Unless you're a supercomputer, you are not developing a stance that trumps a majority of all other stances.
4. This should only be implemented if it can be implemented correctly. If it ends up breaking the game, if people end up with foot dm's because something or another their foot got stuck in the ground or something, this should really not be implemented. If it's beyond Toribash's programming to support a system that allows this level of creative freedom, then do not attempt to implement this. It will cause headaches, it will cause whining, and it will be a total mess.
5. Presets would be terrible. No, no no. With presets, you do run into the problems of unfairness and one stance being better than all the others.
So in conclusion:
Supported if it's implemented without a paywall and it allows (nearly) total creative freedom to the players to create custom opening stances, and is implemented as an optional function. So very different than the original post, but at least I support the idea of stances.