Cool that you see Loons as a nice strong troop, getting them myself in 10 days :P
I'd say Witch, they do good on both offense and defense
Well, I think that many troops are strong in different ways. But, if I were to vote on one troop as strongest, I'd say...
WALL BREAKER!!!
Just kidding! Lol.
I think balloons are best for defense, since they are an air troop, and when they are destroyed, they fall to the ground and blow up troops below them. However, they are extremely slow.
For offense, I'd say wizard. Though PEKKAs are extremely strong, teslas can easily desetroy them. And dragons don't do super well against other dragons. Also, wizards have a decent attack power, and they target air CC troops and are ranged.
I say wizards are good, if u spread them out nicely.
Yeah... lvl 8 mortar plus low level wizard equals a rather large... BOOM!!!
I would say that healers are the best troop in the game. Though they can't heal air troops, I put a healer and some barbs in my clan castle for defense. My healer picked a group of 5 barbs, continuously healed them, and took out the entire army, with the help of the other 9 barbs of course. If there were no other troops in the cc, she heals buildings, and she stays far enough away that archers or wizards can't hit her, and if they go after her, they go into the range of a lot of defenses.