There are actually some interesting similarities between Klopp and Pioli, both needed some time to change from 4-2-3-1 to 4-3-3, 4-2-3-1 was Klopps favorite formation for a very long time, both have big problems with injuries. Both also have problems with bad spells and crisis weeks/months.
While Klopp has a good track record he also had equally numerous seasons where he only challenged for a CL place and has his second bad season now with Liverpool.
In my opinion with this brand of football some of these things like more injuries, tendency for streaks of good and bad form, maybe even less tactical flexibility are somewhat inherent and come with that style.
The most stable style of football probably still is a more conservative approach, but on the other hand football should also be about enjoying the game and not strictly only results.