Nah. A gatekeeper is a guy who loses to the majority of the top 10, but good enough to still beat some of the up and comers. (Jeremy Stephens or Ricardo Lamas for example)
Max still a long way to go before he becomes a gatekeeper. If he remains at FW, he will still only be fighting for the belt or number one contender fights. As of now, only Volk has proven to be at his level.
I prefer if Max stays at FW, for the sake of the division. I want it to remain as competitive as it can.
If he leaves to LW, he doesn't add much to that division* but takes a lot from FW.
*At least not the version that fought Dustin. If he is serious about it, he would need to take a year off to properly bulk up. And would he still be same fighter after that? Who knows. I personally don't think he can achieve the same level of success as in FW.