Interesting, thanks for the detailed report JDiver. Interestingly, I posted some negative thoughts about BA Club Europe after flying IST-LHR back in March I think. I think it was on the BA board, and I was attacked and called a Troll by spotwelder. I'm still waiting for an apology, because apparently a vast majority of the follow-up posts supported my opinion.
My negative comments were mainly directed toward BA's seating configuration (2x3 with only 34" of pitch) on a 4 hour international flight. I probably didn't even talk about the pre-boarding/boarding nightmare on my connecting LHR-AMS flight, similar to what you describe.
As an aside, the D-E-F seats in CE do have some extra width. If you look closely, the seat backs "spread" apart by about 2-3" vs. the "unconverted" coach seats further aft. So you still have to play armrest tag with your seatmate, but the space between armrests is actually a little wider than the regular coach seats. It's still significantly worse than the A-C seats, and if I had gotten reassigned, I would have been screaming bloody murder, particularly for such a long flight. (Similarly, the AC seat backs in CE are 2-3" closer than those in regular Y, hence the "mini-seat" in between). It is a rather ingenious invention how they can convert the seats, but 34" of pitch and the potential middle seat on 3+ hour flights just stinks in my opinion. Irrespective of the competitive landscape for intra-european flights.