Currently, I do think it's definitely exploitable in some ways. On the occaision that my Exos actually do take a hit (or a few hits) that their crazy armor doesnt make them immune against, it can be a rather big hit.... and it just wont matter much. I can finish off the enemy in question and then hit wait a few times to regen, or I can wander off and maybe stand behind a wall for a bit, which also has the effect of getting the enemy right where I want him, or I can just walk away entirely until regen finishes, and finally I can just stealth, move away, unstealth, and bam, regen. And kiting specificallly is very easy to do: if you're on the edge of an enemy's range, which you often are if they're firing at you, you can just walk away and they're forced to keep walking instead of firing more, but if you're a bit further in their range, you only need to stealth for a couple of turns, get to the edge, unstealth, and THEN you can make them follow you.
But more than that it's the sheer strength of the damage reduction and regen that is the issue right now. The mechanics are a bit exploitable, yes, but the numbers are also just too huge. Heck, I'm not at all trying to focus on shield stats whatsoever with any of my team, but they've all ended up that way, pretty much invincible even against strong foes. Most things simply cannot do any damage whatsoever and those few that do, the damage just gets healed after a couple of turns anyway.
Overall though, if the stats can be more brought into line, it could work out. The stats are definitely the main problem here. At the same time though, it should be a bit easier for bots to cause "permanent" damage to you. I've found that that particular part of the mechanics just doesnt seem to go off much at all, which just makes it even easier to tank things. Not that tanking things is a bad idea in concept, but it shouldnt be that simple to do and the tank should usually be left with SOME damage; after all, that's what the Assault's often-largeish shield numbers are for.
On another note though, I also still think the Assault's 50% bonus to shield stats should be toned down. It's not the only Exo that's gone all indestructible at the moment, but it's the one that can do it the easiest, definitely.