We are missing a ton of iconic and highly requested vehicles from all eras.
If the vehicle being niche or highly unusual is a big factor for DCT, then the event will start including post war vehicles soon.
Nothing about the vehicles you listed is out of the ordinary, they have nothing that makes them special.
The Sturmtiger, TOG II, KV-7 and XF5U all are very unusual designs and all of them, except for the KV-7 are niche vehicles.
Most people wouldn’t give a hoot, if the event vehicle ends up being the Ki-64, StuG IV or one of the countless missing vehicles that have nothing to really set them apart from the rest.
Stuff like the O-I, P.43 or Tracteur C would be special in a TOG II way, but only the O-I has a chance of being added and that chance is very slim.
The XP-67 would be special in a XF5U way, but we has a US fighter last year.
Other things that are unlikely to be added that I came across from the WWII era include the Me 323, Bachem 349, the Mistel composite, Schofield and Strv fm/31. None of them are impossible, of course.
So, if we stick to WW2, the two most likely vehicles I can think of are the BV 141 and the T92 HMC. There probably are some more one-of-a-kind WW2 vehicles that I haven’t come across, but I’d say the BV 141 is hard to beat.
If we strip the WW2 requirement, there would be way more options though.