I agree with those things, particularly the 2nd one since the content is extremely scripted and ends up going exactly the same too often. I do personally find lots to do in the first half of the expansion, but it wouldn't bother me if they rearrange things either.
I don't agree with this one however, because there are plenty of examples of 24 people being fine. Alliance Raids are one example, and Occult Crescent CEs, Bozja CEs, CLL, Dalriada and DR are examples of where it succeeded. Arguably, hunts and large boss FATEs are other examples of large scale fights that work.c) It's not worth to invest resources making High End fights for 24 or more people. See what happened to the Chaotic mode, or even worse in the Forked Tower.
The problem isn't the scale of the fight but that they have a mechanic that requires every single person to get it right. 24 people will not universally get a mechanic right, because a certain percentage of them (pretty large percentage in FFXIV) will not be good at them. They should just make 8 people need to get it right. This worked so well for CLL and was a proof of concept. Find 8 competent players then let the others be so bad at the game they wipe 50 times if they want, and it strikes the perfect balance for what FFXIV is.