The point of IC2 solars were that you needed a ton of them to be of any real value. Early on they were fine for a couple machines then you'd have to keep adding more and more which eventually became fairly expensive. It was always generally "cheaper" to make some of the others(Geo for example) but needed more attention which is what people didn't want to give. Solars offer free energy but very very little and to get enough for later you needed TONS of them which is what truly balanced them.
With some careful balancing I think having solar panels still expensive to make but have them generate more energy would work better than it does already, less CPU intensive having a few powerful solar panels than 7 or so solar flowers. I know there is that better solar panels add-on for IC2 (can't remember what its called) but that's kind of a cheap fix, using 8 solar panels to make a low voltage array, then a medium and finally a high voltage array.