Maemo is a great OS if not the very best. If we want to ditch it we probably need the reasons to do so. There is still so much the community is doing for the development of Maemo. CSSU is a great example for this.

I don't actually know how to ditch a community driven OS, though. :P
Maemo is a fairly optimized OS. There are some things that run slow though, like the App. Manager (which I think the CSSU devs could do something about, but are not).

Though creating a new OS is a good idea, but a hard job. It needs to be optimized for the device and probably better optimized than Maemo. We don't want a battery sucking monster. I actually had a similar idea on this regard. I would have posted but couldn't manage the time to do so.

What I had in my mind was creating an OS with support for running packages of different OSes natively on the OS. Why the idea occurred was because there are already so many compatibility layer application softwares (Wine, preenv, apkenv, meecolay to name some). And I believe they can be integrated in the OS to run natively and probably better than they run individually. Though I am not a dev and don't know how hard this nut would be to crack, but anything is possible for the developers (that is how I like to believe at least).