It depends on what you mean by "special." In the early part of his career, Mikita was as likely to shove his stick up your azz as look at you. Somewhere along the line he changed his outlook and actually won the Lady Byng. All of the guys you named were special, of course, but Bobby Hull brought something to the party that set him apart.
Hull had two seemingly contradictory aspects to his game. He was the fastest skater of his day--certainly one of the fastest skaters ever. And he had the heaviest shot: 120mph slapper, 105 mph wrister. Also among the most powerful shots of all time. Couple that with matinee idol looks and the flowing blond hair (of which there is much less these days) and you had something special. Has anybody else been the fastest skater and had the heaviest shot? I can't think of anybody.
The sight of Hull scooping up the puck behind his net and racing up the ice at full speed, shedding checkers like Ralphie, the Colorado buffalo, was something to see. The crowds (Chicago or anywhere else) would let out a sustained "oooooh" as he zoomed toward the far blue line, then an "aahhh" when he let loose with a shot. Goalies admitted they were afraid of him because they couldn't see his slapper coming. One goalie of the day told Sport Magazine that Hull once took an unscreened slapper from the blue line, he brought his glove up to make the catch, and it hit him IN THE BACK OF THE GLOVE! Already coming out.
Howe was in a league apart and a guy who would rip your heart out. And he wouldn't necessarily respond immediately. He'd wait, skate by your bench and butt end you. A nasty piece of work. But look at that career.
Hull, on the other hand, often said he couldn't score from the penalty box. And he was routinely double teamed for most of his career. Another guy on the ice with him whose sole job was to follow Bobby around, try to deny him the puck, then hook, hold and trip him when he did get it. The Red Wings gave that job to the appropriately named Brian "busher" Watson. Hull rarely got into fights, but when he did it was like a John Wayne movie, with guys flying out of the barroom windows. On one memorable occasion Hull had had enough of Watson and just kayoed him, dragged him half conscious to the Wings box, dropped him off like a bag of mail, then took his seat in the Blackhawk box. He once kayoed John Ferguson of the Canadiens, a guy known as the "heavyweight champion of the NHL." Hull had broken his jaw somehow, and the first chance he got, Ferguson applied an elbow. Then his lights went out.
The guys you mentioned were better players, better on defense, who had mastered all of the nuances of the game. But Bobby Hull wasn't about nuance. He was about skating like the wind and firing that howitzer somewhere in your general direction. Not only was he the most popular player in the league by a mile (remember, only 6 teams) he was the face of the NHL, the one guy casual fans would know in non-NHL cities.
One year the Hawks were out of the playoffs and NBC (?) hired Bobby to do commentary. As the network came out of a break, the camera followed Bobby in the Boston Garden as he was making his way back to the press box. And the Boston fans were giving him a standing O. Oh yeah, he was way special.
The rest of us took the cue and stuck to talking hockey with the Jet! 
