Ironicaly, the two items with health bonuses have use issues. Slight mabey, but noticeable nonetheless. This is becuase people have allot less hp in T1, and allot more in T3. Striker in T1 should only lose 2 health, and should lose 4 health in T3. Add the same principle to the guardian, but with more in T3 and less in T1.
Striker is underused in T1, and guardian is underused in T3.
The reason they only seem underused is that people don't understand how to deploy them correctly. People pick Striker for its high mobility, and the recon for its stealth abilities. These are black and white functional advantages that can get you in or out of combat quickly, and preys on the other player's situational awareness... by far the easiest thing to exploit if under developed.
The Guardian on the other hand is defensive unit in a game mode that heavily favors offensive tactics, and in order to fully leverage the shield bubble, combat has to take place within it. One advantage it does have is the personal shield speed is on par with PvE runs... so the shield->strike tactics used in monster fights can be applied to PvP combat. But the shield endurance vs damage is still pretty unimpressive... 3-4 hits and it down. So players can't rely on it for protection, and must still attack in order to survive.
There are also some strikers in T1 Niichi, about as many as there are guardians in T3. Ussualy, they're good players. Also starlin, that's my point.
Basicaly, when you have 5 hp, striker takes away 60% of your hp, but when you have 15, it only takes away 20%.
Also, anyone else think the sheild should be able to bump emenys? Like pve? Throwing that out there.
I can't speak for T1, but in T3 I've seen plenty of guardians in teams. Trying to deal with an enemy team that has a guardian happily shielding in there is not an easy task to do.