I was going to do some housekeeping, tidy up the OP formatting and discuss some of the ideas proposed here and elsewhere, but I got caught up in reading the (silent f) manual. A few observations - 1 there's a lot of great functionality that doesn't get used because the user can't find it. and
2, it doesn't make a whole lot of sense - you can see how new features have been assigned almost semi random invocations - because we want to get them working - and it's running out of space.
3 there's a lot of it.
4 'B' gets used - a lot. Both in the the 'manual' and in this post

I can see why the devs might be reluctant to use 'B' as a back button to the source menu - Of course, it's already used for a bunch of short cuts and as a modifier key press (i mean by this it's often the second key in a dual key situation). There's a lot of coding effort gone into features that are
currently only accessible using the 'B' button. I'd like to suggest that thinking of intuitive ways to invoke these functionalities without involving the 'b' button may be a fruitful area of endeavor. Low hanging fruit, baby.
Even before this, all is not lost - where the b button is used as an alternate press, another key could be used. I'll make a couple of suggestions but I'm sure you can think of others. + springs to mind, opening a context menu, or the down arrow could be quite popular this season..
However, there is a fundamental conflict between using 'B' for back , and using b for gestures and using b for a modifier button.
The 'B button is clearly the only suitable button to to use as a modifier, as it's the only button you can comfortably press while simultaneously pressing another with the same hand. which is why I suppose you have to enable 'b' for gestures i.e it's not the default. I expect using it disables the other 'B' behaviour, is that right?
How about we actively choose to turn on 'B' back button behavior like we do with 'B' activated gestures? Seems a reasonable compromise.
However, a compromise is what it is, i suppose we could have a poll!
"'B' Should be used for short cuts" Pro's and Cons Vs " 'B' Should be used for going backwards" Pros and Cons.
Would anybody like to speak on behalf of shortcuts if I set up a poll?
also,
Can anyone help me set up a poll?

is this a bad Idea? really bored of pissing people off....
your thoughts and meditations are, as always, welcome.
S to the P to the ACEpimp