The correct spelling is tiericide, FYI.
I'm not normally a grammar **** but when I see varying different spellings throughout your post it irks me somewhat.

Ok, let me try to flesh out this idea of mine then.

Right now, we have two issues that face DUST.

1 - The New Player Experience - New players are forced to endure a meat grinder for a long while as veterans continually outmatch them with better suits and weapons. It takes a long time for any new character to acquire enough SP to be able to hold their own on the battlefield

2 - The Veteran Experience - At a given point, veterans hit a cap on what they can do with their chosen pathway. The only option they have available to them is to use their SP on something else even if it holds less interest to them than what they initially spec'd into

To satisfy both of them, you need to find a way to give veterans a way to find deeper experiences in the game while not being at the expense of the enjoyment of a new player. It is to this end that I am trying to find a way to satisfy both experiences.

My thought is that new players would be seen as sort of general infantry. They are good at basic tasks like generic combat but not much beyond that. They would be choosing more generic weapons and modules to aide them in that role.

Then, you have veterans. As a veteran progresses, they begin to find a specific role that they like and proceed to focus their character on that role. They can either chose to be broad in what they can do but not very specialized or focus on a particular pathway that gives them great bonuses but also carries drawbacks. With that specific role, the weapons/equipment they use (say your T2 or T3) becomes more specific as well.

The idea is that by specializing, the character would be able to make better use of the specific gear but that gear would be ineffective to someone that did not specialize.

Here is how my idea would play out.
Player X begins the game as a standard grunt (your medium assault type). They have fun as they can hold their own in this situation but then they decide they want to go beyond that and focus themselves. Player X decides that he wants to be more of the hit-n-run type that is more about sneaking up on an enemy and dealing a quick powerful attack than just standing their ground and going toe-to-toe like they have been.

As Player X skills into this pathway, their bonuses become more about stealth and speed at the cost of EHP. The suits/weapons/equipment/modules that they choose would be based on how specialized they get in that particular pathway. They would trade out the medium suit for a light frame because the light frame coincides with the stealth/speed specialization. They would possibly trade out a basic shield extender for a mix cloak/shield for T2 or a full cloak/no shield for T3. The weapons themselves would become more specialized as well. You would have weapons that gained silencers/muzzle flash limiters with a reduction in straight damage or you would have a weapon that dealt a lot of damage but gave away their location temporarily.