In my opinion, the dragon probably is the best and the strongest troop among all troops from clash of clans.
It is the best because of its ability to attack both ground and air targets.
Unlike other stronger troops like the Golem or the PEKKA who can only attack ground targets.
It can also attack multiple troops within its range adding to its ability to cause more damage compared to other troops.
The wizards can also cause high damage but they cannot take much in return and thus gets easily killed during battles unlike the dragons.
It is also one of the strongest troop in term of hit points when upgraded to its maximum level which is now level 5 after the last game update made by Supercell.
The dragon is most popular aerial attacks during clan wars.
Which means it can last even more longer in battles.
It also the most commonly used reinforcement troop during clan wars for either offensive and defensive purposes because of its innate properties.
When used effectively with the right combinations of spells to use according to the enemy’s base, dragon attacks can be very effective and can win you a three star victory in clan wars.