What is the intention behind designing an ult which, once activated, CCs the target at any range regardless of the actions of the player? To encourage skilled play? There is no counterplay to that.
The intent was to create a more nuanced version of dazzle or cryptic gaze that players had more counterplay against by giving them much more time to react and the ability to use their escapes or simply running to get to a safe zone before being CC'ed - If you have 430 MS and Ghost, for example, you're still going to get CC'ed - but it's not anywhere that the opponent can really *do* anything about.
I've found that with long range skillshot CC's fired from brush (Ashe Arrow, Sejuani Ulti, for example) - the opponents had very little counterplay due to the lessened reaction time - so Nautilus' ultimate was designed to be good from brush but still gives the opponent a lot of warning (For example, The opponent gets the warning particle to run before Nautilus' even finishes his longer cast time) and time to make it back to their tower before being CC'ed, especially in a gank scenario.
We also tried to control the level of CC/disruption by making CC durations that heavily scale with level / situational context - making Nautilus' CC durations more relevant towards the end-game teamfight case - so when his CC's become truly scary, you have more allies that can assist you. For example, His passive and ultimate CC durations scale with skill level/char level and his 'E' slow decays over the duration and heavily ramp up with skill rank.
I was definitely aware of the sheer amount of CC on his kit - but we've learned a lot of things about CCs and their impact from their previous iterations - and so it was a decent experiment on levers to tone back power / grant counterplay to previous CC's that feel overwhelming to fight against.
That said, I admit we could've missed the mark on this one - Feel free to comment on what you feel is over the top, and I'll definitely take a look at it.