Unbalanced leader of intimidating gang? (3-5)
I believe the answer is:
top-heavy
'unbalanced' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
(Other definitions for top-heavy that I've seen before include "Unstable through being over-loaded at the higher end" , "(Of company) having too many executives" , "With upper part too weighty" , "Unstable through an excess of weight" , "Likely to fall over" .)