Every other SZ variation gets zoned out as well, Unbreakable doesn't have to take chip though and his Aura makes FBRCs much easier to deal with.
It all sounds like a bunch of crap, but in reality all the stuff Liu Kang does(zoning, doing pressure, extending pressure, armor breaking, and easily getting in to do pressure) much easier to deal with. Aura deals with pressure and zoning, parry and Backdash are much better tools compared to what 90% have to deal with B1 and various pressure gaps. It's not like Liu has any real mixups so there's no real fear being next to him.
I mean what is Grandmaster going to do to Liu Kang midscreen? Have his clone destroyed by a barrage of fireballs as Liu gets to Flying Kick MB his way in and start doing chip. The only way I see Grandmaster excelling over Unbreakable is in the corner. Maybe I'm just crazy, but I've played with someone who's mained Grandmaster since day 1 and he learned Unbreakable exclusively for Dragon's Fire and doesn't regret a thing.
If any SZ player would go into depth on why GM would be good against a zoning, chip, and armoring breaking character like Dragon's Fire then be my guest.