I do wanna point out that Vortex's weakness is a group of mechs. I'm 5000 SP, in a CPC match a Rank 5 Seeker with Dual Frag 8 tried to teleport behind me and attack me, but instantly got vaporized by the 2 bots behind me, the only thing that i saw of him was him exploding. A Surge can just dash a Seeker when it tries to teleport behind him, Seeker cant start anything against a Bastion unless the shield is gone, Vortex can overpower a Seeker, Nomad can dash into Seeker which gives Nomad a 50% DMG reduction buff + it removes the shield (Seeker gets a 30% DMG buff, so Nomad then has a 20% DMG Reduction buff). Aegis can drop his Dome and make the Seeker spawn outside the Dome, which gives Aegis a fighting chance. Guardian can spin around and try to System Crash and Panther can also make the Seeker spawn on the other side of the shield.
When Seeker targets you, you can see that just like a Javelin lock, when it's teleporting to you, you see a red arrow behind you, it takes Seeker 1 second to fully teleport to you, so you can react to it, note that during that 1 second, nothing can happen to him, so you have to use your EMP and System Crash or Dash ability when its fully done teleporting.
The problem is gonna start when Seeker is being used by a good player. A good player is gonna wait for the right target at the right time. You are alone? Your ability is on cooldown? You are reloading? You are using Mortars? Ahhh... Too bad, that means you die.
I think this mech becomes a problem when it's used by someone that's good with it.