A great post, just a few points to add though.
1. I think that early form under KD can be explained away as 'New manager honeymoon' when some players up their game to impress the new guy. That, and anything following the Roy era would seem like a blessed relief. I think what we have seen this year is a much more erratic and poorly integrated side. Unsurprising, but there are a few worrying trends in terms of gameplay and player quality. I just don't think, having seen the players and play this season that what we saw at the beginnig of his time in charge is where KD actually wants to go.
2. Your points about the old guard finally failing are well made (Gerrard is doing that thing where he phones it in and saves his legs for big matches and England finals). I would add that Kuyt has also deteriorated badly this season and Reina has also looked a lot less spry. Problem is the players brought in to make the transition to the new era from the old have failed to step up, forcing KD to rely on clapped out old fogeys.
3. Your defense of KD I feel is weak, suggesting its the players not performing rather than the manager. The problem I see it is that he brought in too much dross and its failed to perform. that is only part of the problem though, every manager can make an error of judgement (Carroll arrived in a very over-wrought, tense environment, I think that was a mistake made through urgency).
The bigger problem for me is the direction KD is taking the team. When Roy Evans was replaced by Houllier that signaled the end of the old era and the embracing of the new. While Houllier has his critics, the one thing he will always be credited with is starting the club down the road to a more professional era as the old ideas of boot room etc. were abandoned in favour of a more modern outlook. Benitez came in and took that process to a new level; super fit players, modern training methods, computer analysis, a focus on data gathering etc.
The main issue with Hodgson I always had was that he represented a move away from the the direction that Houllier and Benitez had taken the club, he seemed like a step backwards to an era that was no longer relevant, big, strong, clueless, 'domestic' players in rigid 442 formation, battering down backlines and being taken apart by sophisticated intelligent players, players that are now the lifeblood of the top end of the premiership.
When KD was brought in he was hailed as a offering a direct link to the past, the man who would unify the club and heal the wounds inflicted by the old American owners. At the time I felt he represented a risk; yes he could gel the club, but what past would he link to? Would he continue the work of Houllier and Benitez, or would he directly bypass that to the pre-modern era? What we have seen then is a bizarre hybrid of the two, with sabermetric or whateveryoumacallit being used to bring in players while Dalglish seems to place a premium on British, experienced throwbacks to the long-ball, widemen, 442, little-and-large era.
Newcastle was just one more example of this, players like Skrtel, Carragher, Bellamy and Carroll, ideal for a 442 juxtaposed to players like Suarez, Enrique, Gerrard and Spearing, more suited to a flowing, mobile, pass and move style. To my eyes the current side is some sort of horrible chimera composed of two opposing strategies, each competing to see which can be the victor for the future of the club. the problem as I see it is that KD seems to be trying to develop an old fashioned, direct 442 using ill-fitting parts from a flowing, mobile, 4231. Even if he succeeds in creating his footballing vision, I'm not sure that's where the club needs to go, whether the style of football he is trying to impose is even that relevant anymore. My concern is that in the summer KD will attempt to cut the Gordian knot by offloading the likes of Maxi, Kuyt, Agger, possibly even Suarez and bringing in more players like Downing etc. Yes, results might improve, but I can't see the team achieving much more than 5-7th with that template. it just seems too far away from where the modern game has gone.