As far as IS Omnis: not gonna happen, and nobody who's not a lore-hound is gonna want one. They're going to have permanently mounted IS XL engines and will forever be vulnerable to side-torso death.
However, if PGI added new functionality where you could pick an omni-configuration of your selected chassis AFTER the map/mode has been chosen (so you have some flexibility to adjust to the scenario you're about to face) then suddenly Omni's get their famed flexibility, and IS omnis would have a niche to fill that would counteract their fragility.
Edited by C337Skymaster, 03 December 2018 - 12:03 PM.