The quality of some mods, I would absolutely be ok with paying money for.

RHS: Escalation for Arma III would be a good example. Those guys deserve my money, but at the same time I would feel more inclined to use a service provided by Steam (instead of Paypal, assuming the money would still go into an actual back account) due to ease of use.

However, I feel it's imperative that it should be a donation; (instead of the mod being put behind a paywall) due to fact that a lot of mods are interdependent upon one another.

Taking Arma III as the example again; a lot of weapons mods are dependent upon ASDG Joint Rails as the coding "interface" for the ability to allow accessories and attachments to be fitted upon said weapons. If the creator of ASDG really wanted to upset this "market," all they would have to do is put a price tag on his mod.

Even if the weapon mod was "free," you'd still have to pay whatever price the ASDG creator set for his work. The weapon mod creator would have zero control over the price of his own product. Regulating which mods are ethically "eligible" (eg: mods that aren't "platforms" for other mods) would be an absolute nightmare, as definitions wouldn't/couldn't keep up with the industry. All it would take is enough assholes to try and cash in on the zombie circlejerk to make enough Day-Z ripoff mods that's dependent upon RHS: Escalation to lock them out of any profits on their own work.

Then you'd have to deal with the angry mobs of people who previously paid for said mod, before it was stripped of it's "profit" privilege.

It's a noble idea, but holy shit it sets up a scary environment if it doesn't change quick.