He did step up as a heel, but it was marginal improvement and it was a case of too little, too late for him to really anywhere in ROH. (Although, he was pretty good at T.T Wars 06 with Danielson against Gen Next)
ROH usually cycles the roster around, save for a few usual suspects. Lethal, wasn't doing anything to warrant being on the roster.
He cuts an even worse promo then Roderick Strong and that's bad because Lethal is supposed to be a cocky arrogant heel and he can't do that on the promos. Roderick Strong, is in the mold of Dean Melenko. He does his talking in the ring.
Lethal, can get over as face because he has that natural babyface charisma but that is extent of his strengths.