I sort of agree with you and I sort of don't. For example, I think an interesting future path for the Rumprun unikernel (which, I always stress, is not the same thing as a rump kernel) is running without the POSIX-y userspace interfaces. In fact, that's pretty much where I think e.g. Golang support for Rumprun should go, i.e. remove the userspace abstractions from the stack, since they, conceptually, do exactly nothing. Parts of the implementation of Rumprun are wrong, because I didn't previously see the importance of no-userspace, but I'm slowly converting those. (ironically, Rumprun -- before the codebase was even called Rumprun -- started out as no-userspace, and then grew too much userspace ... but that's really another story)

(edit added later so that we get credit going where it's due: It occurred to me that it was Sebastian Wicki who was campaigning for the no-userspace mode last summer as part of his lowRISC project, and did the initial work to be able to again use Rumprun without "userspace". Apparently my memory of events goes only a few weeks back if I don't think about things carefully ...)

Now, if I'm allowed to summarize rump kernels, I'd say the goal is to build a framework which incorporates enough of the past to allow things to work, but tries to be as flexible as possible so as to enable the future. I'm a firm believer in "there's no such thing as #1", which means you shouldn't produce software components which work only in one type of tool, because it's easy to foresee that right around the corner you'll have to build components for the next tool.

p.s. "Atti"? That one was new, usually it's "Antii" or something like that ;) ;)