Smoke is somewhat popular, yes. But Ermac is not that popular at all besides the occasional fan on each forum who obsesses over him. Hes one of those characters that you dont like nor hate. IMO hes beyond boring. His moves suck. He story and background are weak
Theres a ton more characters that i would say are arguably more popular than Ermac:
Kung Lao
Reptile
Baraka
Sektor
Cyrax
Quan Chi
Noob
Smoke
Actually, Ermac is very popular and much more popular now then most of that list. There's three other sites where I've made/seen polls asking about the ninjas and Ermac winded up being second highest fan fav second to Sub then Scorp. Those were the top three.
MKD Ermac on has had a lot of attention and arguably the best revamp story wise and costume wise out of the past few games. Easily out of the ninjas I'll tell ya that much.
Sektor, Cyrax, Noob, Reptile and Quan are not more popular then Ermac. The robot ninjas aren't nearly as popular as Ermac and the regular ninjas.
Sektor-just got really interesting of late but isn't nearly as popular as Smoke or Cyrax overall.
Smoke-was more popular oldschool MK but of late is always someones "pawn" being reprogrammed and never doing anything for himself or deciding for himself...
Kung Lao-just another Liu Kang with a Hat
Reptile-lost lots of popularity over the years, he's always doing the same thing being Kahn's *****, trying to free his realm...and failing constantly.
Baraka-again just another tool of Kahn and the bad guys, but somewhat cool I'll admit
Noob-similar to Ermac with MKD/MKAstory he was never really that popular because of his story, then once it was revealed that he was the original sub-zero(glowing blue eyes) he became more popular.
Quan-Chi-at first was cool but not as cool as he used to be, he's been harrassing and pissing off Scorpion since MK4(even before that if you want to get technical) and pretty much betrays everyone he comes in contact with. He's cooler then Shang I'll give him but power wise he's just another sorcerer.
Ermac-was always popular and cool from a "powers point of view" but lacked in story, was yet another pawn of Kahn however it wasn't his choice unlike some of his counterparts, Rain, Reptile, Baraka etc then once Kenshi freed him in MKD he chose to redeem himself and being good. He also had the best revamp in storyline and costume by most MK fans when he was announced, I remember out of the ninjas Ermac and Rain were talked about the most with the recent MK games alot more then any other ninja by far.