Don't tie new weapon to trait line
Yeah, it is odd that we do not need the trait line to use the utility skills, heal skill, and elite skill, but we need it for the new weapon.
Why the weapon, but not all of the skills?
That was the whole point of the elite specialization. You are effectively assuming a new class and getting skills and traits that are not part of the old class. When you don’t take the elite trait line, then you are not changing your class at all, but remaining as your old class with its current skill/trait set. The new weapons and skills are what makes the elite class different.
Then make the elite specialization weaker and let it be the 4th trait line. It’s too weak in its current state to replace one of the other trait lines.