You're not forced into the Kingfisher, there are other viable Special at those tieirs.
I am personnaly a fan of Last Hope which can save your life. The 5 armor is nice but it's the 15% movement speed that is often enough to get me out of my opponent's range. That said, I usually play Bruisers that can take a hit when below the activation threshold; Last Hope won't be that good on a Sniper.
I believe the Servos are the prefered Tier 2 choice by other players. The 15% movement speed after a kill is nice to chase a second opponent or get away.
As for Tier 3, the Titan Plating are a good early game choice, giving you the equivalent of a free AP in Health which regenerates much faster. I also like the TX Battle Legs, their passive movement speed help move around the map and the Recovery is great on my Bruisers, but again it's not as good on Snipers.
Keep in mind, the Special Augmentations give you the opportunity to get more than just base stats, use it wisely.