You can still have short, stout, mean and dangerous and still have a slightly larger statue that merits the $570 price tag- as opposed to something that is closer in overall dimensions to typical 1/5 scale statues which usually come in more than $100 less.
Not everyone purchasing these things collects every single character associated nor do a good % of the ones who do collect teams and/or associated character display then all bunched up together in one noisy grouping.
For myself, this is pretty much a one off. I won't be buying any other X-Men or X-Men villains to display with him (unless they ever kick out a killer Byrne style Storm or Kitty Pryde of which the odds are likely 0)
Again, the pose he is in would mask a slightly larger scale even if he were in a group setting. 17" hunched over is still going to look "runtier" than 22" standing up.
Besides, stout is a relationship of width to height, not height of one character to another character.