Also, the Vanquisher is a bit mediocre too. And weirdly, the Genestealer cults have a better one, with access to better smoke launchers too!
Yeah, the Vanquisher is really pretty bad at the moment. I certainly wouldn't take one.
My takes on the Leman Russ variants at the moment:
is actually totally fine. It lost the ability to move and shoot everything without penalty, but it's only a scant few points more expensive and basically just as effective as it ever was. It won't be glancing Rhinos to death anymore, but no huge loss there.
is pretty bad now, simply because the main gun is, on balance, no stronger than the Battlecannon (double the damage except half the shots at 1/3 the range) except in the rare instances you're shooting at more than 5 T5 multiwound models. Which, sure, that might happen sometimes, but often?
(with Plasma sponsons) is now only usable if you make it a tank commander and fire on Overcharge all the time (while using the re-roll order). Yes, it will probably still explode, but at least it can kick out a decent amount of damage before it does.
is a cheaper, more reliable, but less potent form of the Executioner, basically.
, stock, is okay, but as mentioned the Battle Cannon is fairly "meh." It isn't terrible, but I think you might be better off with a Basilisk. Depends on how useful you feel the sponsons would be. I can see driving one around as a Heavy Flamer caddy, I guess.
is pretty terrible now. Ignoring cover at it's AP is really not that much better than the Battlecannon in any way, except lower strength and shorter range.