I don't think it is a big loss, tbh. Heyman hasn't cut a money promo in years, instead being very content to cut the same Brock promo every time he's been on screen for the past 2-3 years. Brock proved during his first WWE run, then his first UFC run, that he doesn't need a mouth piece. Bringing him back at all seems like it was more of a favor to Brock than anything.
Brock Lesnar does not need Paul Heyman to hype him up. Let him do his tour circuit and hypnotize the goy with his rabbi cadence while he calls himself a genius in 30 different ways. He wore out his welcome for me back during the Punk feud, then proved he was death to anyone that wasn't Brock.
Maybe he'll find something more interesting to do with EVOLVE or something.
I could have SWORN just a couple of weeks ago that Double Talk Dave was reporting Heyman had no contract at all, but was on a pay per appearance deal, and was bugging WWE to do something with him so he could get some money.