I mean he got them out of the relegation, he's not a terrible manager.
I find it quite funny that pundits are falling over themselves in the rush to criticism the owners for sacking Ranieri, these would be the same pundits who criticised his appointment in the first place.
The timing of it is a little hard to comprehend. Though they lost their last champion's league game, the score was a creditable 2-1 that gives them a chance (however slight) of getting through to the next round. Certainly didn't deserve to be the camel's back breaking straw.
Their form in Europe has been good all season, but they just aren't turning up in the PL and that is what is important. Since the start of the year they have won one game in all competitions and that was against Derby in a replay. I think the owners just looked at the results and then the fixtures coming up in the League and felt a change was needed.
If Leicester hadn't won the League last season I don't think anyone would be questioning the decision. As the owners said, at some point you have to pit your sympathies aside and make the pragmatic decision.