how long do you play the game? Isreal is an example how bad it is to add nation with few unique vehicles. Same story is Ukraine, Jugoslavia, Czechoslovakia etc. Sweden is one of the potent trees. Ukraine until 1990 has shared all vehicles with Soviets, this tree we have in the game allready, and the 6 new vehicles want make the tree any better. But to explain it better, see Italians, France or Israel. The problem is they have 1-2 vehicles for each BR, that means players die and after one dead they leave the match. This is not good for gameplay at all. More trees in the game with few vehicles will on make this problem to grow. So what is neede to do first before adding any new tree, is to solve the MM and how the game works. And then we can talk about trees with few unique vehicles. Becouse it is allways harder to play against germans or soviets, USA which can spawn up to 5 vehicles each match and nation which have barelly 2 vehicles. I can imagine it more to add this vehicles as special vehicles for tasks like BP or events like this one , summer - winter , But to create a new tree? It will end up like China, we will have to grind all those T34s and T 54s up to rank 7 where will be one Oplot a and BTR.
And BTW I am from Slovakia, I know well history of Czechoslovakia Industry, our T72M2 was event vehicle and I am happy about that. But what else did we had? Really not to much.
But I fully suport idea of combined nation tree, and there can be a place for rare vehicles. But to be honest Gajin needs something also for the events, with more trees the garage will be empty within 2 years.