I would actually have preferred it if Morgan found a working ECM unit when they found the blackbox's and it explained him more than the Phantom Mech ability. Same with Yoringa, or Patrick Kell.
But that isn't the way the story is written.
The 5W with 9 Missile hard points is a chance for the kind of insane looks I like. I really wonder what it would do with 9 Streak SRM2 slots filled, lots of ammo, and a big standard engine. With the cooldown mod and range mod, light mechs would hate you.
the "phantom mech was ECM!" stance does not address why Patrick Kell, driving
Ardan Sortek's Victor, pulled off Phantom mech during the rescue of the Silver Eagle.. While the victor was left with the Hounds for repairs, they'd have
never have installed a special totally secret lostech device onto a mech they're gonna ship out to a davion general.
further patrick, after the battle, says that he finally understands Morgan.. which means that he had no clue how Morgan pulled it off either, yet he managed to do it himself anyway.
it also presupposses that Yorinaga Kurita liedwhen he said he learned how to do phantom mech via meditation and philosophical musing.. and it means that Yorinaga, who is super-loyal to the Coordinator, didn't turn over a priceless bit of lostech that could mean victory for the combine if studied..
basically it just doesn't work as a tech based effect.