What makes Crimson so cool is not the Librem 5 specific stuff. The software developers for not L5 specific related stuff are continuing developing mobile software and all that stuff will come to Crimson as well. So for example Phosh is already 6(?) versions ahead and we will get it. Also the file manager has improvements we will get on Crimson (better touch screen support as far as I know) and so on. Also if Mobian makes something upstream to Debian, we will get this, too.
Battery uptime is a huge amount of work that gets bigger as more optimized things are. The easiest things are done and any further improvement will need more and more time. I don’t expect much here and see this as very long time task. Especially the idle state of OS as well as applications need much work.