So, all of the Ranged Mercs have High Health/Low Movement Speed. This makes perfect sense since Long-Ranged weapons in this game are really accurate and spammable so that high Movement Speed wont help you one bit. In close quarters on the other hand, high movement speed can lead to you jumping from one side of the opponents screen to the other (even if he has Max FOV), which is much more helpful.
So, all of the Mercs with ranged weapons (Fragger, Sky, Arty, Redeye, Vassili especially) have high health/low MS, to give them kinda equal chances at long-range combat. All but Kira. She has 90/450 distribution which leads to her having only 75% of the other Fire Supports Health and thus dying 25% faster while the speed is nearly useless for long-range combat because all of the long-range weapons are insanely accurate and spammable. She dies to the Gradeur with one Head- and one Bodyshot while she needs multiple Bursts with her weapons to kill any opponent at those ranges.
In close quarters on the other hand, all the cqc weapons are way stronger than her rifles, a shotgun kills faster, an SMG kills faster and the full-auto assault rifle kills faster.
This in addition to the fact that she doesnt have a useful explodydendron loadout (with at least one other useful perk), while others have one AND the fact that her Laser is useless indoors as opposed to, say, Skyhammers Airstrike, makes me feel like she really needs a buff. And from my personal experience, many players seem agree on this because even tho it is Kira free week now she isnt really played that much, while there are proxymines at every corner.