8 actually, at least two of which are optional and used to fill Expert roulette.
Sort of. The environments have enough changes that you can't quite say they just reused it in a lazy way. Sometimes we go through different sections of the dungeon that we didn't previously as well.They did hard mode dungeons back in the day which reused environments
People used to say that Amdapor Keep was hard because of Demon Wall. The big pulls in ARR were always rough, and still can be if DPS is low but obviously we kill them a lot quicker than we used to because of potency and battle system changes and syncing down (which we didn't in ARR). Higher level food also provides an advantage because of how it syncs.they weren't actually any harder however, just more boring one and done content
If these things aren't a problem now it's because the damage of an average DPS that doesn't know what they are doing is higher. High damage parties were always good but you didn't always get those in the past, when jobs were more sophisticated and there hadn't been years of stat, potency and scaling changes.
- Stone Vigil HM can still give people trouble with the pulls or the second boss.
- Wanderer's Palace (both versions) have bosses that I've seen give people trouble not to mention how many people have died to tonberries or pulling too much or pulling into pink areas.
- Tam-tara HM has some pulls that could cripple you with status effects and I would often see wipes to all of its bosses, and the last boss of Haukkee Manor HM.
- Pharos Sirius would wipe at various locations from the pulls, to crystals, to bosses and it is only the gradual difference in average damage output that this happens less often.
- The last boss of Copperbell Mines HM, Brayflox HM, Hullbreaker Isle and very rarely Sastasha HM would wipe.
- The second boss of Qarn HM often would as well because there is an adds check and a DPS check to interrupt the needles cast and a cover mechanic.
As we moved into Heavensward, the hard mode dungeons were just normal dungeons. Maybe that is in part that we had more utility than in ARR, such as Clemency and Equilibrium on PLD and WAR. The sync was also very poor. I was farming dungeons like Hullbreaker HM, Gubal Library HM and Sohm Al HM in 270 with strength melds and destroying those dungeons which were designed for 200-230. Lost City HM I remember the trash hitting hard before we got into the final tier, but that's it.
They could make it even simpler by reusing all of the dungeons exactly as they are and just adjusting them to remove telegraphs, rescale health and damage output to be more devastating. But they went with making entirely new ones only.