The morale of the story is that a great game creator can use limited resources to build a decent product regardless of what their using as long as they have the knowledge to do so. This involves learning programming in general to debug on any tool, understanding image compression and such for optimization, and mastering a tool of your choice whether its C2 or unity.
That being said, I will list some personal drawbacks for construct 2:
1. The updates after R168 have a bit of issues on native browsers for older samsung devices (S2,S3,Galaxy nexus). This is bad for anyone that wants their games sponsored, but even so there are workarounds. But it would be nice if it was fixed.
2. The scirra team keeps posting templates of popular titles which ruins the fun out of creating the game yourself. When the flappy bird template came out, we had thousands of flappy bird clones. Although it's a marketing ploy it would probably make the engine more professional if we didn't have so many template options that kinda does everything for you. This is one of the main reasons why we have so many people that aren't able to master C2 and complain about it. Hopefully they make less templates of popular titles in the future.