cast sequences do not offer the same hands off approach that Blizzard found issue with in castrandom. Our castsequence and click macros do not decide anything. Everything they do is explicitly mapped out in advance.

Now, take a normal person, playing one character. Would you tell them to use a massive /click sequence in order to raid? No, you wouldn't because they would put that player at a disadvantage to players who use shorter castsequences and watch their timers for refreshing debuffs/stings/hots/whatever.

There is nothing gained in a longer castsequence or use of commas and usually people who depend on them give up some flexability. That whole "refresh stings every X seconds" castsequence is all well and good....what happens when you miss? What happens when the poop hits the fan and you have to spam some other keys for a bit? Now your timing is all off.

There was none of that tradeoff whatsoever with castrandom. There was no reason at all not to use it, and you didn't have to plan out or think about anything. Just throw all your random crap that you occasionally might find useful or never remember to use into one long castrandom and never worry about it again. This is why they changed it. It made using cooldowns and situational abilities essentially free passive DPS.