The main difference is that Klopp, Pep would have brought in players in the Summer that would suit their style. They would also coached the current crop of players and improve them.
Look at what Klopp had when he took over and send them to EL final:
A terrible, terrible backline. A midfield base of Can and Milner, injury prone Sturridge, average Lallana and probably only two good players in Coutinho and Firmino.
Still he made them play the style he wanted and you can see his imprint right away.
It's a very poor excuse to say Klopp and Pep won't do anything with our current squad.
What Klopp worked with at Pool when he took over was worse than what Ole inherited and by a good margin.