While Ksante has some of lowest win rates, if not the lowest in certain ranks, this is not due to Ksante being underpowered. The primary reason for this is that he is hard countered by certain picks. These picks are unfortunately for him, the most popular champs in recent meta's. It is normal that certain champs have hard counters, however the problem with Ksante is that he either has hard counters, or he default wins a lane. You do not even need to be good with Ksante. Obviously, as with all champs, skill, wave management and ganks can turn a losing lane into a winning lane, however with Ksante, all of this matters much less. 

Another reason for his low win rate is that tanks in general struggle to carry games in solo Q. 
All of these are problems that are part of the reason he has a low win rate, however that does not change what his kit is. In any matchup where Ksante is not countered, he wins by default unless he in playing poorly himself. This means that it is not that Ksante is hard countering the champs, but that Ksante himself has no exploitable weaknesses. You simply need to counter pick against him, or lose lane. You may win through wave management and ganks, however you will never actually be able to play into a decent Ksante. Any misplay makes the matchup impossible.

Every single other top lane champ has a healthy list of matchup's they counter, or are countered by, and then there is a large number of champs that are simply skill reliant. This is not the case with Ksante. His lists are in only two categories. Win or lose.

The reason for this is Ksante's overloaded kit. He is either vsing someone that can deal with his kit, e.g. Fiora, or he isn't. Despite having a high skill ceiling, the ceiling becomes irrelevant due to the nature of the champion.

Ksante is an extremely unhealthy addition to the game. His counterplay is entirely champion based, not item or gameplay based. It is due to these reasons that Ksante is either hated or ignored. If you play champs that auto win, you wont care, and if you play champs that auto lose, you hate him. As someone who has played both, I can assuredly say that it never feels satisfying to play into a Ksante. You either stand still while he dances around you, or you chase him down like a dog. It is almost never skill based and is almost always purely champ based.

These are most of the reasons why Ksante is unhealthy for league and should be removed.