Seriously blackblades? with that name you should know they will Never give a man of Color to much air time nor that kind of money as a actor on Any show.
for example : the show "The Game " on B.E.T network all black cast except one . The Entire show surround the 1 White character why? in all cast black show, to pull in White demograph? . so why would a black speedster be important in a White tv show ? im very Sure that is the Real reason Keiynan Lonsdale left. directors had nothing to offer him with meaningful substance to add to the show or to his credit as a Speedster . don't be surprised to see him on Legend of tomorrow with rest of Flash has-been .

Blackblades this about what really going on "Behind the scenes" not what they want you to "see". you don't suddenly die or suddenly leave a High rated show unless creative difference took place . in layman terms Lonsdale Agent or Lonsdale himself disagreed on something . therefore a departure is made .

P.S.
when a actor dies off any show good or bad is because creative difference or other cast members hate he or she or contract disbute of payment ( salary ) anything else is 100% BS