updated to reflect new edit on first post on 6 jan 2014
love the slash as a separate key. Tab is also very welcome. I adhere to _wb_'s post: compose mode is better.
As for the freed up keys, bring paragraph symbol back , and stick the yuan (W), rupee ® and ¤ (O) currency in there... also ruble and peso. My guess is that each country liked their symbol there. I use the euro, and the dollar to program. I have no love for the pound, but english ppl do. Sure, you can meta+equals, then L to get a pound, but a single key is faster. Or maybe math simbols would be übercool... a pi symbol, sigma, what about FN+shift being yet another layout? (ascii art symbols!)
Also, the audio on the back... I'd put the power charger there (missing?) and the audio back to the front, as the SOC will be about where it is now, because that is the coolest part of the pandora when held with 2 hands, and you need the audio as far as possible from that noise generator (actually, the screen is the noisy one).
Nothing on the sides, keep it like that, my hands are there.
tl;dr: headphone jack to front and altGR on R2 for more custom layouts.