I feel red dragon is the best lvl 5 creature.
Of course it is situational what is the "best" but avarage i think it is the winner.
Green is a bit two slow (initiative), Black or Archdemon cannot be healed, others cannot fly/slow or cannot be healed.
Its special attack is great.
The only weakness that somtimes fire damage can be worthless
I miss Titans from Homm