He is not as under powered as Whiskey Foxtrot but just like Whiskey Foxtrot there is no good reason to pick him, he is a huge squishy target with weak melee damage early game.
El Dragon is a big easy target with very low 975 HP and no ranged attack until the level 3 clap mutation. I am fine with how squishy he is since he has a good deal of gap closers and and escapes on relatively short cooldowns. The issue is that he is a large soft target, his early game is terrible and his mid/late game is not strong enough anymore (due to the nerfs) to justify playing him.
Any competent team can completely shuts him down early since hes a large targer and he does not catch up until its too late. Its too easy for ranged characters like Marquis or even melee characters like Galilea to completely push him out of lane preventing him from gaining exp.
He is a very fun champ, I still play him regularly and do well with him in solo que. Unfortunately in any kind of 5 man premade match he is easily pushed completely out of lane since he has no range, no sustain, and low health.
P.S : His passive appears to have been changed back to 3% melee damage per stack, but may not be working correctly as it has not been mentioned in any patch notes.