Bug#1027215: How much do we lose if we remove theano (+keras, deepnano, invesalius)?

[Rebecca N. Palmer]

theano has been mostly abandoned upstream since 2018.  (The Aesara fork 
is not abandoned, but includes interface changes including the import 
name, so would break reverse dependencies not specifically altered for it.)

Its reverse dependencies are keras, deepnano and invesalius.

It is currently broken, probably by numpy 1.24 (#1027215), and the 
immediately obvious fixes weren't enough 
(https://salsa.debian.org/science-team/theano/-/pipelines).

Is this worth spending more effort on fixing, or should we just remove it?