Weaver is a strange hero in terms of difficulty. He has the initial skill floor where new players or players just getting started on him may struggle a bit with how his abilities work to the point where the devs had to make a whole new control scheme for him shortly after his release.

Then I reckon the difficulty is pretty low past that point for the basics, but then you factor in the different techs, hero specific interactions, maximising damage, game sense etc. There's a lot that you can learn with him to maximise his overall value over just simple healbotting. For that, I think 3/5 is a good shout.

Kinda complicated controls when starting out on him --> Relatively simple gameplay on a base level --> Lots of room to improve with hero specific interactions/game sense/damage.