In MusicBee, the Now Playing list is your playlist. Looking at Foobar again now, I see it has a library where tracks are selected and a playlist to send them to for playback. How is that any different?
You can achieve the behavior I'm describing by creating an auto-playlist of your library, loading the foo_queuecontents plugin, and adding its panel to your layout.
That's why you wouldn't really load your entire library into the Now Playing list (unless you actually wanted to listen to every single song you have).
I do, in fact, want to listen to every single song I have.
In fb2k (and previously, in Winamp), I create an auto-playlist from my library, enable shuffle, and begin playback. When I want to listen to a specific song, I use a hotkey to load Media Library Search (or JTFE in Winamp), hammer out the song title, and hit enter. When I want to queue a specific song, I do the same thing, but hit "queue" instead rather than restoring the application and rooting around through my library. When I want to listen to the rest of the current album, I use a hotkey to disable shuffle. When I want to skip three tracks ahead in an album while shuffle is enabled, I use a hotkey that disables shuffle, skips to the next track, and re-enables shuffle -- three taps, and I'm on the song I want. Predictable behavior enables rapid-fire workflows like this, while the current MusicBee queuing paradigm will only slow me down.
When I'm not managing my library, I want my library management program out of the way. Again, there are many, many reasons I'd like to migrate over from fb2k, but I don't believe I should have to spend my day looking at MusicBee to accomplish simple playback tasks.
I'd suggest spending more time using MusicBee to get used to its way of doing things before asking for such a major change just because it's slightly different to how other programs do things.
Actually, as ma_t14 points out, all the requisite functionality is already present -- all that would be needed is an "Enable Now Playing?" checkbox, which, when unchecked, would move the queue numbers from "Now Playing" to playlist views and replace "Now Playing" with a queue contents editor (as in foo_queuecontents or JTFE).
I think the important thing to consider here is not the audacity of my request, but rather, how many potential users are being turned away from MusicBee every day because of this and *don't* come to the forum to complain or suggest a better way. By simply including an option for what I'm suggesting, that's one less barrier to entry. Surely that has to be a good thing?