Personal taste, your set-up looks good, but lacks dynamics. Spidey looks good perched on the garbage can, but might look better perched on the column behind him or coming over the rail. Move Hawkeye above behind the rail. Remember, the Hawk likes his perch. He can see better from up there. Spread the others out and give their poses a little life. The diorama itself looks just great. Now breathe life into it.
Ryan