Healers don't really need their current skills downshifted any more. They need more DPS skills at low levels to emphasize what they're supposed to be doing between their healing so they're drawn into exploring that section of XIV's combat (which then trait upgrades with the usual DPS skill upgrades past ARR so we don't over-complicate it). ARR and HW's healing balance is actually good with the current toolkits and the newer tools do come at appropriate levels. The problem is tutorialization. People aren't using new options that are often redundant if you know what you're doing, but if you don't you'll probably need them way more than you realize. That's the issue.

Tanks are similarly fine. Get them to put on good gear and they will be okay for 1-30. After that they actually have to start pressing mitigation, but if they wore bad gear pre-30 they probably learned to do that, so one way or another they 'should' learn a problem. What SE should be doing is teaching them to put on good gear. Specifically if it's as an alt job.

Some DPS do need it, but it mostly comes down to lack of core tools that really should be available early, like at least one AoE GCD on all DPS by level 30. The transformation that happens from certain classes to their job equivalents during ARR's also hampers these toolkits quite a bit. Most jobs here are getting some of those core tools in that 30-50 section. They're not getting it earlier because their arc hasn't reached that point yet.

Really what's a problem is Melee and Tanks all feel practically the same at these levels. 1-2-3 dominates the level 1-30 process and it makes every single class suffer. But it does work very well for a completely new player on their first go, if they're willing to engage with it. And that's the intended audience for that content.

Of all the jobs or roles I haven't mentioned, Summoner's the only job that really sucks now, but that's a problem with the new rework, not the levelling process. It sucked more in ShB because of bad tuning. Stormblood Summoner was well balanced throughout its process in a way that players completely ignored because tutorials are hard.

I think the real problem is just that ARR is slow without the "Road to" buffs and while it is good at teaching players to pay attention (unless you get a vet blitzing because it's SLOW AF compared to current XIV fights) it doesn't teach them how to play very well. And the only way to fix that is to use job quests for tutorial content, which isn't happening. I'd like it if players got access to better rested exp bonuses for reaching each expansion's level cap, so that after getting their mains to endgame they could just permanently have access to "Road to 50" levels of boosts for any jobs they left in ARR, and have rested EXP apply to quests like that boost does too.