Riot is choosing champions that are strong in the meta.
As in akali is a very strong champion, but she does not fit the meta:
not ranged AD, is not support.
Mid is countered by purple ward.
Top is an easy target to gank, and since akali only defensive ability is smoke screen, the enemy jungler will probably buy a oracles, which will pay up easily, due to clear wards and seeing akali in shroud, up for easy kill.
Akali jungle, is very weak, low clear times, bad ganks, counterjungled easy, not much sustain. Good side is mid can always have blue buff.
And akali is only one of the champions that suffer from this. Riot should increase the number of champions to at least 15. This way they can keep the ''in the meta'' champions, and put in 5 more who don't exactly fit it.