I can't really comment on OS suggestions for the LEAF, but I do have quite a strong opinion on the ipod controls.
Ipod controls on the LEAF are VERY DISAPPOINTING!
I'm surprised this hasn't been noted already. The system is extremely primitive. If you switch over to AUX with your ipod connected, it automatically starts playing the first track listed in alphabetical order. This list of tracks includes podcasts, and other non-music with audio (videos, etc.). Believe me, if you use your ipod in the LEAF you are going to get VERY SICK of that first song!!
Why? Because it plays every time you connect to the ipod and continues to play as you try to find the menu, and then continue to click through to what you want to play (e.g., podcast). And there is no quick, easy way to scroll. So if you want to play tunes that start with anything past 'P' its going to take a while to get to them! And podcasts get interspersed with song tracks, so the list is especially long. You can't control anything from the ipod itself, it is locked out; you are forced to use the Nissan system. It will take a minimum of four or five screen touches to get going, while the first track plays.
Once you get what you want to start playing, the Nissan ipod control system continues to be disappointing. The total length of each track is not presented (so, e.g., you will have no idea how long a downloaded podcast might play for). There is no shuffle songs option. It seems every time I plug in my ipod, I find something else to grumble about.
Which is really too bad. I have become accustomed to getting news, entertainment, etc. from my ipod in the car and to some degree, rely on it. So much so that I'll probably continue to use the ipod in the LEAF (despite the significant annoyances!). I'd have thought Nissan would have been able to handle this; most are going to be disappointed with this feature of the car. I hope they improve it asap! It is fairly maddening.