Personally, as both a dev and a purchaser, I don’t mind the approach you’re talking about @Noolarch, but I also would give favor to plugins with full source, and which will have a license similar to that of the content license (one time purchase, unlimited titles). I’m not sure how I feel about seat licensing. I think it tends to be annoying much of the time, but would probably be fine for plugins with source, since presumably there won’t be a ton of hands touching source anyway.
I understand things like a whole script engine being closed off - that’s alright by me, but for smaller plugins…eh - I’d also expect a higher level of support for any closed-off portions of the source, since when something goes wrong I won’t be able to fix it myself (not to mention issues with versions being maintained, long term usages etc. where full source is essential).
I’d prefer not to deal with tiered packages and stuff, beyond a simple split between indie/hobbyist devs with a certain revenue cap per year (like $100k/yr) and AAA and bigger indies which make more than that. I definitely think it’s fair to charge those larger companies more for an unrestricted license, of course.
Overall though I think it should be kept simple… not a lot of tiers or splits between pricing models etc, and a clean simple to use license.
Obviously though some of that will be up to the developer and I imagine more complex and tiered schemes will be supported, but the above is my personal preference and where I’ll be putting money towards.