The older (pre ShB) content feels WAY too easy.

[Silver-Strider]

It's a combination of gear, poor ilvl synch, toolkits becoming more potent than the content was originally designed around and nerfs to old content that have left the majority of old content being pretty easy. Sure, there might still be the odd boss that has a mechanic that can kill people (Nael in T9 has probably stood the test of time best out of all pre-SB content but even they aren't infallible) but overall, an overhaul of massive proportions would be required to fix it.

A bandaid fix of fixing ilvl synch to match the ilvl of when that content came out would help it at least a little bit but the fact they didn't use the stat squish to reel in potency bloat as well doesn't really bode well for them ever revisiting old content to make it harder.

[Bravura]

As a player who joined in the summer of 2021, my experience has been that the game is way too easy. When 95% of the content is easier than the latest Kirby game (which I totally recommend btw!), I think it can become problematic and even numbing. Many dungeon runs have been unenjoyable, even impossible to properly experience, because party members just run, invincible-like, through it - so there's never much talk about strategy, either. The lack of difficulty is not soley because of the gear stats I think - it also has to do with how the game has been designed and planned up until now. This is not to sound sour, FFXIV has many great aspects that I love - but it's a bit low on adventure and exploration, and challenge. It has enough players, surely, to cater to those who'd like to see more challenging, less hand-holding-like, open-world (in the sense that there are no artificial barriers placed to avoid you from ever running into challenging mobs) content.

Disclaimer: I did play a lot of FFXI and vanilla WoW.