Managers can only work with the raw materials they have. Koeman didn't trust our defence, and he bought Bolassie, hence the long hoof up the wing. Now he has had a chance to work with the defence, and a chance to buy 2 players and bring through 2 youngsters who he can mentor the style has changed. I very much doubt he had world class players at Feyenoord, and he certainly didn't at Southampton. You say Pochettino built Southampton but when he left half of the team was sold and Koeman had to start virtually from scratch, which he did very successfully.
I have no doubt if Koeman went to Barcelona he would do fine there, and if he stays with us and is given enough money I think we will challenge for top 4 and be in the top 7 every year.
Dave you are somewhat blinkered by your admiration for Martinez and I understand that. The first season he was with us, I thought we had the perfect marriage of a pragmatic defence and an attack that would take a risk, which they never would under Moyes. However, that was a false dawn and Martinez reverted to type in the next 2 seasons.
We are building something under Koeman, most Everton fans can see it, and a lot of neutrals and media pundits can see it as well.