The other piece of the puzzle is that we know we're pretty good at what we do but I'm a former theme park designer and that doesn't necessarily translate to UI and graphics 1:1 so it would be nice to bring someone in to up our design game there, likely on a short-term contract.
And finally, we'd be learning a completely new skill to rebuild the backend and get us off Parse by the end of January when they fold. There are bandaids available for that situation but if we're going to go through the time and expense, we'd prefer to do it right.
So ultimately, my original question plays into your last question, "Why would an investor want to invest unless they believed you were at excellent growth?" I'm hoping the answer is something like, "because these other metrics and circumstances point to a high enough likelihood of excellent growth being right around the corner." But I don't know if that's how the funding market thinks right now even if I can convince someone to believe that to be the truth as much as I believe it to be, so I'm hoping to gain a little insight there.
An investor would certainly prefer investing if it was the case that you were growing so fast that you couldn't handle the growth. The skeptical investor in me would ask: why can't you two get it growing faster without other people? How much longer would it take you to build these two large features with just you two? Which other things are you spending time on right now that you could stop using time for?
I feel these are valid questions given you are building a social application that makes money from advertisements, where to make large amounts of revenue requires extreme scale -- therefore why would an investor want to invest unless they believed you were excellent at growth?