I'm thinking of some ways to make Metamath more accessible and more visually appealing.
Here's a concept art for axiom usage minimizers, for example.
(Blue colors are variants of Choice, red colors are either ax-3 or an axiom best avoided, others were randomly chosen.)
In single-theorem view, each proof step could have such a usage mask (we
have 60 axioms not mechanically eliminable in
set.mm right now, which
fit into 5x12 grid neatly) and would allow to easily see the offending
step.
Also among ideas is a better theorem search, which would not suggest steps unprovable from assertion's hypotheses, but it seems to require both SAT and some model of set theory. (A large language model might also fit; it must be remembering lots of math of various levels, to be thus able to generate counterexamples or proof guides.)
I'm yet checking how to parse the database, handle its parts and serve as a website; metamath-rs looks able to do that but it's documented a bit sparsely.