As a totally impartial observer, I would say that all in all it's been a successful season for Leicester.
As long as they avoided relegation, which they secured with those 5 consecutive league victories after Shakespeare took the reigns, it was far more important for them to make the most of their Champions League adventure and progress as far as possible in that competition, than to finish a few places higher up in the league.
They have done something which Man Utd and Chelsea haven't achieved since 2014 (3 years without a deep CL run is a long time for clubs of that size), Spurs haven't since 2011, Arsenal haven't since 2010 and Liverpool haven't since 2009, reach a Champions League quarter-final. Yes they had a easy group, but then again they've had a noticeably weaker squad and smaller wage bill than those other clubs so it all evens out. And many of those bigger clubs have messed up in easy Champions League groups over the years anyway.
Even if Leicester had finished 17th this season, than relatively speaking they would still have a had a much better season as defending champions than Man Utd in 2013/2014 finishing 7th or Chelsea last season finishing 9th. And now they look on track to finish in the top 10, adding further gloss to this successful and historic season for them.