My main gripes with this game

[Shurrikhan]

Reprisal's effect used to be on Rage of Halone (as a physical down) and of course it wasn't aoe, Flash is effectively just replaced with Total Eclipse now except it actually does damage.

Except the fact that you had only Sword Oath, your AoE had very little spam value (as it did nothing but inflict enmity and a diminishing Accuracy debuff that only saved perhaps 1.5 healer GCDs over its full duration), healer ST damage had far greater relative significance (especially on WHM), and your optimized damage came at cost to enmity, literally changed what was optimal for your whole team. Once Shield Oath was given earlier and PLD was given AoE worth spamming, that entire dynamic changed. The two at-30 playstyles more different than alike.

I remember how guides said to target enemies in order but in my experience BLM aoe made that not a good strategy for the tank.

The guides were sound. At level 30, BLM-BLM, BLM-BRD, and BRD-BRD were the only comps for which it would not be optimal to (CC-)focus-target when running a PLD, since the PLD itself lacked AoE and had high ST damage for its level via its full combo and the at-the-time rather massive potency bonus of Sword Oath. The damage lost from Flash and additional healing requirements from lack of CC and any one enemy dying slower was greater than the what any single BLM could gain from the ppgcd advantage of AoE over ST. Even among those three comps, it was a toss-up.

Remember, back then periodic damage did not break sleep or bind -- only direct damage did, and many more DoTs (Bio, Bio II, Touch of Death, Shadow Flare, Flaming Arrow, etc., etc.) had no initial damage. You'd use the few that had direct damage, (AoE-)Sleep, and then burn in series, often killing everything such that not a single heal is required for that fight (beyond a pre-Adlo/Regen).

That's completely untrue. There have always been sprouts everywhere on most servers and the game has been flooded with new players for many, many years.

Even now, in probably some 70% of my Leveling Roulette runs, my entire party is level synced down by at least some 10 levels.

Presumably that's just to make me wonder why the point in common between a 58, 64, 73, and 80 is... Dzmael Darkhold?

Balancing. It's something that 'that game' doesn't have.

Mate, XIV is no more balanced across the leveling experience than WoW is. It's probably less so, actually. Not that such particularly matters. The reason for the down-sync is as has already been described, the no-win compromise they'd otherwise have to face between lower-level players, in having a more limited kit, being shafted on maximal performance or higher-level players, in being forced to use their full kit at scaled-down value, being shafted in terms of effort required just to do the same as (or barely more than) lower-level players.

[Jeeqbit]

The guides were sound. At level 30, BLM-BLM, BLM-BRD, and BRD-BRD were the only comps for which it would not be optimal

Optimal crumbles in duty finder though because they usually don't care about that.

Even now, in probably some 70% of my Leveling Roulette runs, my entire party is level synced down by at least some 10 levels.

Presumably that's just to make me wonder why the point in common between a 58, 64, 73, and 80 is... Dzmael Darkhold?

That doesn't mean they are not relatively new to the game and it doesn't mean a whole lot overall because if you have done thousands of dungeon roulette solo queues over these years then you have almost always had a first time bonus. If you have made alts on non-congested worlds then there have been new players everywhere for years, even in Stormblood.

[Shurrikhan]

Optimal crumbles in duty finder though because they usually don't care about that.

Whether people cared about it or not, those behaviors were the norm at the time, hence the difference between the level 30 experience now and the level 30 experience then. To say level sync lets one experience the given content as it appeared in a previous expansion is more than likely going to be just plain wrong.

[1] That doesn't mean they are not relatively new to the game and it doesn't mean a whole lot overall because [2] if you have done thousands of dungeon roulette solo queues over these years then you have almost always had a first time bonus.

[1] That a party member is nonetheless new to the game still has no reason to send a party who are at minimum half-way through Heavensward to an ARR dungeon (i.e., to content to which none of the party are new).

[2] I have done thousands of roulettes, yes. The slight majority of my 4-mans had no first-time bonus, and only some two-thirds of 8-mans (minus MSQ roulette, which have even then about 50/50) had such. That's precisely the point. Yes, roulettes help players get (inadvertently, their first) queues, but it's not as if the every time n people hop into a roulette that at least 1-in-4 players will be one such adventurer in need of a first run. That's precisely why we often end up randoming into dungeons no one matched into the roulette group specifically queued for.

It's just a reward system. Outside of Sprout surges, it functions to most players' satisfaction regardless of whether it picks up a bonus or helps someone actually in need.