Let me name a few, and everyone else can add more:
The early beta bundle submachine guns,
the Lag (an advanced 37mm variant—I hadn’t even heard of it!),
the Italian Panzer III N (which ended up as a copy-paste and would be better suited at BR2)
the Panzer IV Command variant (now able to withstand 76mm shells from the front),
the Soviet Valentine (intentionally nerfed in WT—all equipped with 6-pounder guns),
the German rocket vehicle (lacks proper artillery and should be moved to BR3),
the M8 Greyhound (should be in the TT like the Puma, given its high production numbers).
Ahh the old Greyhound, I bought that a long time ago, and it was a long time ago that I actually used it. I think I bought that during one of their sales as I would have never considered paying full price for it…
This thing—underpowered, sluggish turning. I’m thinking it’s probably just too poor, even as a flamethrower vehicle. It’s already from the Finnish Campaign and still being lumped into World War II. The Soviets probably still have some thin-skinned flamethrower tanks they could introduce.
I just remembered an advanced squad variant of the MP40 with dual magazines, but it got moved to BR3. I’m thinking it’s just faster reload speed, so why does it have to go to BR3? The MP40’s firepower has already been nerfed anyway.
I really miss it. It seems like df has forgotten, but such a basic aircraft should be offered as a starter pack, just like the BA-10 or the I-16, as a toy for collectors or newcomers to use early in the grind.
The main issue is that this vehicle’s firepower and penetration are inferior to even the standard M3 tank. In the Pacific theater, it should be able to zip around and maneuver quickly, but in this game, wheels feel like a debuff. Plus, it’s an open-top vehicle and, because of its wheeled design, can’t turn on the spot. Its firepower is also worse than tanks equipped with dual machine guns or flamethrowers. I really wish it could be added to the tech tree.
Panzer III N (which ended up as a copy-paste and would be better suited at BR2)
I think I bought that during one of their sales as I would have never considered paying full price for it… 
