I think some characters need a size change. By size change I mean a change in their appearance to make them either taller or shorter (mostly taller). A few characters I think need this are:
- The new Iron Man
- Colossus
- Dormammu
- Juggernaut
- Ronan (maybe give him a reskin too)
- Hulk
On a side note, while we're talking about size, where's baby Groot? I'd love to see this...

But with this,

And this