The only question I've got is since I've never played on a ping lower than 280 (that's the best I can get), will this have a significant change effect or this will be like everyone will have the same ping/delay as I have? If it's the latter, then that would be awesome.
I play at an average of 415 ping. Yes I'm jealous of people who can get anything lower than 200. I've tried it and the difference is astronomical.
I'm not sure if I got it right as well. But global c/d is when you can't press 2 skills simultaneously. It's like counting with your fingers by two's and by one's. Counting by two's will be some sort of trial and error.
GC-D to me is like any or most MMO games. You can't press skill 1&2 at the same time of the fraction of amount of time. The theory behind it with pc games is already evident in some videos posted here and on youtube. In PC games, you press skill 1 first then repeatedly press skill 2 to catch up with the GC-D. So it won't make any difference in game play the way I see it.