I think it's easy and fine to just change the gatekeeper prefs (under "Security and Privacy") to "anywhere" for a month or so. But after that you should change it back to "Mac App Store and identified developers."
What's the point in that? For a month or so, your Mac is "fair game" so to speak. Once you re-enable GK, you put yourself back in the same spot you were trying to avoid by disabling it. You've gained nothing but a month of keeping yourself open to the world.
All LEGIT Mac developers are registered with Apple and have been for years. Some need a little time to update their apps for Gatekeeper. It's not a big deal.
That couldn't be further from the truth. All of the development tools for OS X are free and don't require registration. On top of that, you've got the large number of developers who use "non-standard" tools to develop applications that don't require any Apple tools other than access to a Mac. For instance, me. I develop applications using Python and Vim, neither of which require me to have any contact with Apple in any form. And, last I checked, I'm a pretty "legit" guy. I'm not even sure I'd say that most are.
It's no more "big brother" than Apple requiring an admin password before allowing apps to alter your system.
That's a false analogy. That's like saying that a car maufacturer that tells me where I can and can't go (GateKeeper) is like them saying I need a seatbelt (admin password). An admin password doesn't hamper my experience or, by default (since /Applications is system read/writeable), prevent me from installing applications. GateKeeper on the other hand does.