No sense of fear in this game.

[Ibi]

In FFXI[, ...] Getting past enemy lines wasn't just something you stormed through like a bull, you had to be sneaky which added to the risk and the enjoyment.

Sneaky is the word, sure, but only because in 95%+ of areas, you'd just cast a spell or use an ability/item to gain the Sneak effect (and sometimes also the Invisible effect) and could then completely ignore all the mobs.

This is already a thing, just most people don't realize it. Most mobs won't aggro on you if you're out of their LoS, but there are exceptions. Walk past a Mudpuppy/Ninki Nanka sometime. Seriously, walk right in front of its face. They can't see you, so they only attack if they can hear you (i.e. you are running near them). I think Morbols and a few other things act the same way. Mobs in the Diadem aggro on you when you get in range whether they can see or hear you or not, so arguably they aggro to your smell.

Yeah, FFXIV definitely still has the sight/sound distinction. In addition to what's said here, you can walk right up behind something that's aggressive based on sight, all the way up to its hit box, and it'll ignore you. Try to do that with a morbol though and it'll attack right away.