animation cancelling?

Its called bad coding and champ favoritism

It depends on the champion and the skill. As far as I'm aware, it mostly affects skills that are on-hit. It's a small burst of power by most efficiently managing the timing between your basic attacks and skills, but then Riven's power is extremely dependent on that timing, and it gives her a much larger burst of power because of her passive and the way her skills work.

[(https://www.youtube.com/watch?v=mr6m59_1_A0&t=0s)] most disgusting animation cancel i know of or beautiful depending on if you like unintended code*[sg-jinx]*

Some champions need it as a part of their kit, while others don't, most of the time they arent intended and Riot will decide if they want to keep it or not and rebalance the champion after. An example would be Riven who got rebalanced when her animation cancels were "discovered".

V4.5 Stats Base armor increased to 19 from 15. V4.2 Stats Base health regeneration reduced to 2.5 from 5. Valor Valor Shield strength increased to 90 / 120 / 150 / 180 / 210 from 70 / 100 / 130 / 160 / 190. V4.1 Stats Base attack damage reduced to 51 from 54. Attack damage per level increased to 3 from 2.75. Broken Wings Broken Wings Damage per cast changed to 10 / 30 / 50 / 70 / 90 (+ 40 / 45 / 50 / 55 / 60% AD) from 30 / 55 / 80 / 105 / 130 (+ 70% bonus AD) Valor Valor Shield duration reduced to 1.5 seconds from 2.5

These were the first nerfs in season 4 after she grew popular after season 3 worlds.

You can learn more about her and why her animation cancels were allowed in her kit here: https://www.youtube.com/watch?v=l9lcyDjUSec

I am ok with some animation cancels, but i would preffer mainly and to be unable to animation cancel.

can hide his W Q Q E combo in animation of his leaping autoattack :P so 2k dmg hidden in 0.5 sec... is complicated. Its the best thing about her kit, but also the worst imo. It allowes her to do R Q AA Q AA Q W AA R E (or something like this idk i hate this champ :P) in insanley rapid sequence lasting as long as her Q knockup and W stun... She can delete you in unhealthy fast time.

kit would be great for assassin if you could actually cancel R with W canceled by Q canceled with E1 into E2, but you cant so its OK, it only deals shit ton of dmg right now... So he is what Rengar and Riven should look like, just force them to play their spelll animations...

Can't say much about others, but for at least Riven in particular, it's because they thought it was cool in the past and now it's impossible to actually remove from her kit because it's too ingrained in her kit. She's been balanced around it for too many years and too many people are used to it for it to be removed unless Riot full-on reworks her.

For most other cases, it's either a similar thing (It's been around for so long it's become expected behavior rather than a bug) or it's just too minor of a cancel to matter. If Ashe could get her E animation off faster by canceling it with R, that'd have so little impact that it just wouldn't be worth the time, effort, or risk of extra bugs appearing to fix.