Here's what I think (for what it's worth):
The base is paramount to achieving the fundamental background BIR taste and smell. I don't believe a decent BIR curry will be made without a good base.
"Proper cooking" of the spices (some might say "singing" - to extract their volatile oils) is paramount to achieving the fundamental taste and smell. I don't believe a decent BIR curry will be made without it.
The use of ancillary ingredients (e.g. capsicum, garlic, ginger, tomato paste, dried fenugreek, fresh coriander, salt.....stock?) just adds nuances (and readily recognisable tastes and flavours) to the BIR taste and smell.
The problem for me, I am absolutely certain, is that if you put my curries alongside the best BIR curries of the 1970s and 1980s, they would pale in comparison (though my wife disagrees..I just asked her!). But I know it's true.
To me, it is true, that this forum has been more focused on the base. "Technique", though often mentioned, has never been well (if at all) defined (in my opinion).
I am glad to see that you (the, so called, 'Fantastic Five" have put an emphasis on this).
To be honest, it has always been there and, obviously so, it has always been important to cook the spices optimally (whether cooking traditional Indian or BIR dishes).
And, to be fair, it has been mentioned often. In fact, to give credit to Andy (of RCR fame), he repeatedly pushed the importance of "fusing" the spices with the tomato puree at the early stages of cooking. Similarly, Pat Chapman has always emphasised the importance of the "bhoona" process (i.e. frying of powdered spices). Perhaps not enough emphasis has been placed on this for newcomers to easily grasp and appreciate (sorry if that sounds degoratory, I don't mean it to be so).