1) I would argue that it does not have content for multiple audiences. If the last step of the relics asks you to use the highest lvl of crafting/gathering in the game, there is no point for other audiences to actually interract with the content. The whole content is should be classified by it's most difficult lvl.
3 and 4) I totally agree, but I blame the lack of proper tutorial for high lvl crafting. You can craft nearly everything, even most the recipe in the collection books (I forgot the name), without actually interacting with the crafting at this lvl. So yeah, expert crafting appears as a wall, because the skill needed course has a sudden peak. As often XIV is very bad with teaching its mechanics, and rely on people going to seek information on a third party website/community. Which is asking too much for 90% of the player base.
Most players don't play game to go search the needed information elsewhere : it's more chore than something fun, and it feels so frustrating because of how different things are from their standard experience. I wouldn't even say it's because people are used to use macro. Add to that the fact with each extension, some skills are removed, some other added, to the point you have to relearn the whole thing every 2 years, and your knowledge that was perfectly fine at the time is not anymore.