I'm actually starting to think it's too generalist in a bad way. It doesn't do enough fast enough and is inevitably killed.
I've been making a lot of funnels lately to test with, and I don't remember many games where I'd have not preferred to have spent my metal elsewhere. They don't have enough impact for the cost, and if an opponent scouts it (which they have ample time to do) they will have the real counter to it well before your funnels hit critical mass.
In my opinion catapult, dante, and krow are just better in the majority of situations. Compare two funnels to a fast dante push into bertha, or to a nuke.