The frigate is a bonus ship though, it should be better then the base MRS in some way.
Maybe remove the delay but keep it so the MRS has to be stationary to repair while the Medic Frigate can repair on the move as its special ability?
D.
That, and the frigate does not have innate cloaking, each individual ship has far fewer repair beams (not sure about cap repair beam count though), and it can't repair without losing any externally provided cloak. And as mentioned, it is a bonus ship type.
Not sure if a "delay" of 0 seconds would prevent cheesy abuse though, even if it couldn't repair while moving. A delay of 1 second maybe? That would be enough to stop cheesy "move, stop, repair a tad, move, stop, etc" type tactics from making the MRS almost as OP as it was before.
And it may very well be that the Z medic frigates, as they are now, are OP for similar reasons that the old MRS was, and the current MRS is closer to what the intended balance target for offensive repair capabilities are supposed to be.