1: It's Mars, not Ares. There's a difference between the two.
2: The shield passive is certainly meme-worthy, but I wouldn't say it's the main gimmick about him like Bristleback is. I would say that his Ult is, summoning a circular arena that damages enemies that try to leave it.
I haven't kept up with dota 2. Is it still infested in the lower rankings with macro scripts people install to "play" for them and auto-raise them in the rankings, making their team work extra hard to win while the macro-bot feeds the enemy team? Because that made the game completely unfun.