Those guys would hang out while the mono mixes were done, and then leave the studio or work on other songs. As a result, any stereo mixes prior to Abbey Road were intended to be subordinate to the mono mixes (from an artistic stance). To be honest, the stereo versions are still worth many listens, and they are by far the dominant versions, but they sound wrong in places. One of the biggest problems is that the bass track is often only in one ear, which gives the illusion of congestion when compared to the other channel. Furthermore, some embellishments end up getting overexposed, perhaps sounding out of place. When you convert the track to mono (or if you have the real thing), every sound falls into place like a puzzle. As for Sgt. Pepper, I don't think the album's concept makes sense in stereo, because in mono it really is like sitting in the crowd with the band in front. That's my opinion.
As far as I know, lots of audiophiles on a certain other forum tend be split on whether the "White Album" is better on mono or stereo. I like both.
And as for the box sets, I can wait patiently, since the albums were previously remastered by MFSL (but no CDs were produced). Good luck trying to beat that across the board.