Originally Posted by metaphysician
That's not Ant-Man's only problem:
1. Imagery. Most of the more successful super heroes have a solid, iconic look that you can use to make them instantly recognizable. Ant-Man. . . not so much. He's had a million different appearances in the comics, and none of them are particularly striking.
2. Personality. Most of the successful super heroes have a strong personality hook you can use to sell them as characters. Ant-Man. . . has basically no personality of note in the comics that you would want to even consider using in a movie.
A character's look is almost always tweaked for film appearances. In some cases the film versions of their costumes look better than the original comic book ones. Marvel has a very good track record of adapting and improving upon its characters' costumes, and I imagine that Ant-Man will be no different. Ryan Meinerding and the concepts crew have undoubtedly been hard at work coming up with innovative costume designs.
As far as personality is concerned, the film versions of these characters often differ from the comics in significant ways. To take the most famous instance, the Tony Stark moviegoers have come to love is a radical departure from the staid, somewhat boring playboy billionaire comics fans were familiar with. The origin and basic motivations stayed the same, but Stark's behavior and charismatic presence were quite a departure from what came before. I was a major Iron Man fan, but I was pleasantly surprised by his portrayal in the films as a manic genius, haunted by his past failures and driven to protect the public from his own creations. There is no reason why Wright would be bound to make Ant-Man as vanilla and boring as his comics alter-ego if he follows the Iron man example.