Yea I agree about the Aizen thing. Don't understand why they wouldn't send out at least one member of 0 Squad in order to save SS from him. Supposedly the whole point of Ichigo coming to the rescue from Hueco Mundo was that he was the only one who had not seen Aizen's shikai and therefore was not subject to the influence of his illusions. Being in the RG, I doubt any of them besides possibly Hikifune had previously seen Kanzen Saimin, which would make them immune to it's effects. If they are as powerful as expected, one would think that Aizen could have been defeated much earlier, way before he transcended with the help of just one member.
The only plausible explanations I could think of as to why this did not happen are:
1. There are strict protocols set in place such that the RG show up if and only if the residing CC is without a doubt destroyed. Their appearance is contingent upon the failure of the last defensive hope, that being the CC. The RG are an absolute fail-safe who are initiated only in the most extreme circumstances.
2. They knew Aizen's intentions and could not risk opening up a pathway for him to reach the SK. Once they enter the SS or RW, there has to be a way for them to return to the Royal Palace, which I guess would be the Tenchuuren, and that was just too great a chance to take when they knew Aizen's sole purpose was to reach the RP and destroy the SK.
I can see why they did not interfere before, because even if everything in the RW, and SS was destroyed by Aizen, the Soul King could over time eventually fix everything, as long as he survives.