Just adding my two cents to this thread.

Today, I went to check in for a flight to LHR and noticed my seat was changed from a business class seat in the front to a business class seat in the back.

Upon further inspection, I discovered that it was an equipment change. My original seat was on a plane that had the old seats. The new plane has lay flat beds, and fewer of them than the seats on the old plane.

Given this, the seat change is reasonable, and although I don't like being in the back, it was the only available aisle seat, so it seems they respected my wish for an aisle seat.

I do share the concerns raised in this thread about random seat changes. I have had seat changes on a prior CO flight that put me into the worst seat in business class and didn't respect my wish for an aisle seat, but I don't know if it was an equipment change (doubtful, since it was GUM to MNL and I doubt there are many substitution options on that route).