Okay, let’s do the math: Marquis, vs my Toby, and let’s give them the best damage numbers possible on straight shots.
Marquis at 10th level, I believe does 350 on a straight shot against a shielded opponent. Toby on a fully charged Railgun round, does 300 against that same opponent. Before Marquis can damage my Toby’s 961 shield, he must first chew through my 1k Force Field. That’s three shots of no damage on me. As we also exchange fire at the same rate, that’s three 300 shots in my favor, or 900 points already done against the Bowler Bot, more than likely killing him(I’m not sure how much health Marquis has, but I doubt even with shields, it exceeds 900). Remember also, that the Force Field will eat the last full damage shot against it, even if that shot destroys the shield, so I’ve taken no damage.
But, let’s imagine the game’s bugged and somehow, there are repeatable number of Marquis facing me. So, another Marquis pops up, and we exchange 3 shots again. My 961 shield, vs his 350x3 for 1,050. He’s just done 100 points of health damage to me. But again, I’ve killed a Marquis who traded against me. Also, by this point, my FF is now off cooldown, and it’s back up, so not only are my shields regenerating, my health is as well, and I have my 1k wall up again.
Marquis number 3 steps up to the plate, and we trade shots. Again, 3/3, he dies, I’m alive and my FF’s deactivated again. But here’s the wrinkle: if that fight’s lasted longer than ten seconds, I’m back up 70 health and probably full shields again. My FF also regenerates my health at 7 points per second. ten seconds behind it, and I’m 70 points up again, so I’ve only taken 30 ACTUAL damage that I can’t regenerate.
Now, this ISN’T a real fight; it’s just a numerical simulation of us trading our best non-cooldown shots at each other and defending as best we can without dodging. In that straight trade, at 3 Marquis deaths for 30 health damage I can’t regenerate, with a 1,388 health pool on Toby, it will take 138 Marquis Deaths…to kill me ONCE.
The wasted damage of shield damage, almost universally trumps any kind of damage resistance or extra health unless you have a really strong HR mechanic. Kelvin’s health pool is massive, and using Chomp’s LS can offset the damage he takes. But all of that comes at the cost of reach and control. Kelvin must get to within Melee ranges to make his plays. Tanks like Toby and ISIC, are literal battleships in game. They can range fire across the entire map, and generally have excellent escape maneuvers when they get jumped. This doesn’t imply they’re perfect tanks; I don’t know any that are. But no amount of damage from a Defender character, will edge over their sheer survival potential. Trading that, for a few more points of damage per swing or shot, weakens them more than it strengthens them.