How can you compare 8 man to 16 man?
When you did the 8 man content you were probably in full 150's (63's) - after a week of doing all the content - or maybe even two weeks - if you jump into 16 man you would be a ton more geared.
I bet 8 man is a walk in the park after doing 8 or 16 man the first week - just as you are saying doing 16 man after doing 8 man is.
I hate this argument anyways, no side will ever win and it is fairly pointless. Do whichever you think is more fun. For me, I like having more people with me even though they are frustrating