We are all victims of our own success eventually, i.e. the Peter principle, but to take a few of your points
- The issue wasn't the sale of Walker, it was 1. How he handled the situation when Walker made it clear, 2. Not adapting to a player that wasn't Walker (or adapting to Rose not being the same player he was either)
- You hit on what's Poch's biggest flaw, he relies on young, hungry players that blindly believe in him and will run themselves into the ground mentally and physically, Him not being able to manage Dembele like other managers at Spurs managed King is a horrible statement, Dembele has literally come out and said he could have played the games, his body just couldn't take Poch's training. The failure to help the team win anything broke the belief, and the older players broke first ..
- To me, the blueprint for Poch's success was there, transition to a team that has young +a few key experienced players, focus on getting the best out of Dele, Son and Eriksen (Kane is a given), manage Dembele, change the system from a FB overcommit model to a higher reliance on AMs (we have a lot of depth there), find a way to incorporate newer players faster into system (a year+ is too long to make an impact), work more on tactics than outrunning the opponents (again I see Eriksen as example, under Poch he consistently ran more mileage than all but top 2 or 3 midfielders in the league, is that what we really wanted from fudging Eriksen?)
Said it before, hindsight makes it easy and maybe it makes hypocrites out of us all .. but success was there for him .. he wasn't good enough