Opening principles had given way to guidelines by my day, with Grandmasters doing extensive opening preparation, following Botvinnick and the Russian school. Opening lines were subject to concrete analysis and lines were chosen without regard to opening principles, but only with regard to the positions they eventually created. Us poor mortals, without the steel trap minds of grandmasters, still trudged on using guidelines(principles) as we seldom face the few lines we have managed to commit to memory, and even those memorised lines are incompletely understood. We augment the principles with thematic ideas from the openings we play, like the exchange sacrifice on c3 in the open Sicilian.
We, the masses, have picked up the simple lessons without catching the caveats: doubled, isolated, backward pawns are bad, bishops caught behind pawns on the same color square are bad, protected passed pawns are good, a rook is worth 5 pawns, bishops and knights 3, except bishops are better than knights.... All of these are true, but .... We often miss the buts. Part one of Watson covers what has been told to us following Nimzowitsch, while emphasizing the nuances.
In part two. Watson takes some of those positional principles head on. The bad bishop is not always bad. Watson quotes Suba several times, "bad bishops protect good pawns". A knight on the rim, may not be so dim. Sometimes it is best to attack a pawn chain at its head.
I think in large measure, Watson's book is great success. I am gaining a great deal on the first reading. It is an advanced book, and there are better books for class players to read first, but I think it is an important book for those of us who are trying to break beyond class play. As we prepare our openings with a view toward the middle game positions we want, we should not get bogged down in classic principles, but really understand the trade offs that exist in our tabiya. As Fischer said,"One must give squares to get squares". I think that Watson might expand that to we must give concessions to get concessions. If we better understand those concessions than our opponent, we have an advantage.
Suba's book is an entertaining read, but hard to understand what he is driving at. At times his book seems like an advertisement for the hedgehog. At others, he seems to me, to be pointing his finger at empty air. Several people have commented that they had to read Suba's book several times to begin to understand it.
I am not knocking Suba here, good chess writing is hard. Chess is heavily dependent on those "right" brain functions that are hard for the "left" side to put into words. Good writers that understand chess well enough to put things into words are very rare. The best like Purdy, Silman, and Watson are unique, and yet, they are not grandmasters. Perhaps we are all blind men describing an elephant. If so, I think Watson has felt more of the elephant than most.