First of all the Trident was a remarkable aircraft in its day. Yes, Trident 1's were underpowered and even the T3
with it's 4th engine 'booster' wasn't all that. Apart from poor power to weight ratio the Trident was highly innovative in design, especially autoland mentioned before, later wing design with slats, up and over passenger doors (similar to the Tristar), some seating configurations with rear facing seats (like on a train). I flew on the Trident a few times and never thought anything about rear facing seats.
The unfortunate thing about the Trident and I suppose many British aircraft of that era was Government interferance, strong influence over design by one carrier (BEA), poor marketing and funding. The original DH
121 design was deemed to be superior in perfomance to the B727 original design. American Airlines may have chosen the Trident over the B727 had it had the original specification. BEA's preference for reducing the spec for their own specific market put an end to any AA
How differently things could have turned out.
I can't help thinking, if British design engineers are so good and tend to produce some very innovative products, why is that we just can't get the orders in? I suppose it could be a case that innovation, and being first, is not always a good thing. Comet vs. B707, 1-11 vs. DC-9/B737, Trident vs. B727...
Are we just rubbish at marketing and listening to a broad customer base, or was/is there some other factor at work that puts a nail in the coffin.