I have to say, for our first trips to central Florida, I was always looking for an indoor pool, too. Off hand, I don't think I ever stayed somewhere with an indoor pool, but I will tell you in more 35 trips over the last 15 years, I have never missed not having the indoor pool. And the truth is - I was the one that wanted the pool. It was always just "part of my vacation" to have an indoor pool.
Many of the pools in Orlando area are heated (including the ones at Disney) and that's really all you need. I've been in the pools when its in the 60's outside, but the pools were nice and warm.
I would focus on picking the best resort you can afford that has a heated pool over staying somewhere with an indoor pool that might not be as nice.
Good luck!