Is Gyrocopter a weak hero?

I've played him a few times and I think those games could have been better if I picked a different ganker/support hero. His stun is unreliable because his missile is extremely slow.

His nuke, Rocket Barrage, is only good in 1v1 situation with no creeps in the way. It's similar to Leshrac's edict except the range is very short and Leshrac's edict goes through magic immunity and damages towers. Also, you have to stop to start Rocket Barrage, wasting time that could have been used chasing the enemy.

Flak Cannon is ok. It's only worthwhile if you have good damage output.

His Ultimate requires enemies to stay inside a small area for a long time for it to do lots of damage, which also requires Gyro to stop and go through the animations. It's unreliable and serves little utility in teamfights except additional firepower when there are better heroes that can impact teamfights more.

Did I play the hero wrong? Or is Gyrocopter a weak hero?