Eh, stuart has it's RNG moments, but it's not in need of a change yet I feel.
Rng can play a huge part. 80% of the time I find stuart to be a solid unit that excels more at probing the edges where lone squads may be ninja capping. It cannot solo blobs or supported weapons teams.
For example, i lost a stuart last night on langres because it got caught on some logs, got fausted then was not able to get away from the blob (3 Squads) that pursued it halfway across the map. It died eventually to multiple fausts.
Yes, it can wipe squads on occasion if clumped. Yes it can chase down a solo squad on occasion if they are not supported. Yes they can wipe a rekketon on occasion if it is not supported. But many other units, abilities and mechanics do the same thing.
The issue is more that it is difficult to kill rather than the damage it does.
All that said, axis, ostheer in particular could do with some breathing room. Reducing build times for med bunker, t2 and packs would all help. A generalist mine or cheaper teller mines would also help.
The captains supervise ability could also be moved to vet 1