Back to the original premise of the thread, I find almost no fun in the 4-star content. Working my way up through 3-star prior to the patch was fun. The 50 items for artisan tools was pushing it a bit, but was acceptable and made 3-star feel like a real accomplishment.
Making the stuff for the 4-star books was fun (no sarcasm). It was a good challenge and I had always wondered just how far I could really go if quality didn't cap at 5000ish. I can see how most people would have a very hard time pulling it off, though. I really don't have a problem with some stuff being gated behind a high skill requirement.
I quickly figured out that the grind and/or cost for Ehcatl Sealants and MCDs was simply not worth it. People talk about how it should be hard to gear up 8 classes. Point taken. I recently priced out gearing two classes at 16 mil in only those two materials. Fine. I could spend 16 million gil to gear up and what does that get me? Well, I can make i110 stuff. They cost 1-3 million in materials each. Ouch. If the equipment is for my personal use, I could get poetics for i120 and soldiery/sands for i110 for a modest investment of time compared to how long it would take to make 25 million gil by crafting.
Well, I could make 4-star to sell for money, right? Mats cost 1-3 mil per piece, and other people are attempting to sell i110 for 2-5 mil on my server. I90 hardly had any buyers at 1 million Gil when it was comparably new. Why would i110 have buyers at 3 million? Overall monetary inflation isn't that high. Crafters would want to make their own. Raiders get better gear from raiding. About the only players I can imagine in that market at that price are RMT buyers, and demand from them is apparently fairly weak. Based on the Tells I get, it costs quite a bit of real money to buy that kind of gil.
At the end of the day, the risks outweigh the rewards and the costs outweigh the benefits. By a long shot.
P.S. There was a part of the last live letter where one guy was explaining to Yoshi that it cost him 1 million Gil to get his Supra and Yoshi was reacting like that was too much. I find a bitter humor in that because it currently costs 3-4 million to make one on my server.