Well... I do not know if this is the proper place to put some generic considerations... I'll jot them down anyhow.
I believe that what determines the success of a (web) application is:
1. its functions
2. its user interface
]project-open[ success depends heavily on its super duper richness in terms of functions. It actually is so rich that the majority of users will be more than happy to use just its core/common functions. So porting/updating efforts could (and should) concentrate on these core functions and could somehow leave alone, at least in terms of priorities, not so common, exoteric functions, used by a limited set of users.
But, apart from functions, the user interface also matters, and it matters a lot. And it is not just a question of actual user interaction, how the users actually use the system. Unfortunately it is also a matter of fashion. And here I'm afraid both OpenACS and ]project-open[ fall short. They are still kind of stuck to Web 1.0 style. But Web 2.0 has come, and it has gone too... Now it's time of Web 3.0, see for instance https://www.geeksforgeeks.org/web-1-0-web-2-0-and-web-3-0-with-their-difference/
or
https://nicepage.com/doc/article/20348/web-design-3-0-when-your-web-design-really-matters
Please stay with me, I know that the majority of this is only "fashion"; but it is "fashion" that matters a lot.
Now offering OpenACS or ]project-open[ on top of Docker is not going to rejuvenate the products, neither porting them to the newest versions of their base software components, libraries - it just makes sure they are going to work in the near future for their current users.
But if we want to make sure OpenACS and ]project-open[ will be still used in a future to come, and by new adopters, we need to work heavily on their user interfaces.
