I haven't used Rum in anger, but I do use reagent at work, and there are compatibility tradeoffs not just with other libs but also React itself that storing lots of state outside of the component tree in a mutable ref causes.

There's potentially a lot of work to be done to support React concurrent mode, which has a measurable impact to the user experience of apps that we build. Following best practices set by the React team - including using hooks for sharing and composing behaviors - sets us up better to take advantage of that in the future.

Ultimately though you don't need to rewrite your Rum/reagent apps, but instead there's an onus on the maintainers of those libs to build scaffolding around their lib code and encourage their users to migrate in a direction that will benefit them.