Well, there is still not enough information to say that specialization is really necessary. I would argue only half the classes actually have choices on the skill tree, while the others merely provide an illusion of choice for those who have not looked into the math. But I'll outline it below:
Hunter - an actual choice between offence and defense since they added the Flash Guards. Before they fixed the stances, I would argue defense was the only worthwhile route. But since no one dies in on hit unless they are significantly underleveled (and they just started allowing you to access areas underleveled), Fury becomes the only real choice.
Ranger - the only real option is to grab weak bullet and the weak hit advances. Since you are over there, you will end up getting the standing snipes. Jellen Shot was useful, but they reduced its power and created Deband Cut to add insult to injury. And we will not talk about traps.
Force - I will consider this a "half decision" as the only decision point is after acquiring the charge PP regen. At that point it becomes "stay the course with fire" or "make lightning cheaper." Ice is not a real choice.
Fighter - no choice at all, besides getting double saber gear by 16 or by 45.
Gunner - no choice at all, once you realize how weak the chain system actually is.
Techer - There is an actual choice between support and damage here. It is probably the one class where you do actually have to think about what you want to do.
So, I would say the odds are it will be less like Techer, since Techer only happened once. Most likely the left side of the tree will overshadow the right (as it does in most cases). And if bow and katana upgrades are split, the highest multipliers and most general use ones will be easy to access, as with Fighter, thus destroying any sense of actual choice.