I just mentioned in another post that I'm not sure RAM is the problem. iOS7 probably needs to be better optimized. My Nexus tablets both have 2 GB of ram and I'm still having problems with them....even after the update to Kitkat. I think iOS7 got rushed out the door as they fired the previous iOS boss before Jony Ive took over.
I agree that iOS 7 needs optimizing. But it needs optimizing because it's already stretching the boundaries of the hardware.
It's sort of like saying you can better organize your stuff and fit into a tightish house, or you can get a slightly bigger house and not scramble to stay as organized all the time. Ideally, you'd stay organized and still have a bit of extra space to spread out, because you're going to keep adding more stuff.