I strongly disagree. I'm a developer myself, and I know that managing contributions can be a burden. But in 99% of all cases it isn't. You're still the main developer and can always reject other people's submissions.
However, it may actually save you time! There are features that others are willing to work on themselves, or fix bugs themselves. All of this benefits you (and by extension every user of Q2A) because now you don't have to do that work yourself.
Also those people that actually start digging into the source code and try to make something work in their own time are usually the most passionate users of a product. Leveraging their energy is very, very valuable.