I would like to see Classes treated as proper, separate "Jobs"

[Shurrikhan]

During 1.x that was solved with favor classes and optimal level on gear instead of required classes and level (can wear every gear, you just get a bit of stat penalty if wearing it with the wrong class or level) and leves (8 every 36 hours) and behest (every 30 minutes in a camp) as the way to level up. MSQ and sidequests only existed to tell a story, not to level up.

< (Some 200 levels covered during legacy, from 1.0 to 1.23)

Agreed on the optimal gear, but to be honest, the penalties were pretty harsh, and the cross-over opportunities they offered depended more, imo, on the fact that every job could use most primary stats in some way. Lancers were Strength, Piety, Dexterity, with Archers their inverse, etc. Mind was a useful offensive stat along with a healer SP source.

That said, I'm not sure the sheer lack of exp coming from quests (albeit of an an average higher quality) can be called a "solution" to quests being primarily spent on a main character and nothing really remaining to make the alt leveling experience similarly lively in a similar fashion. Inevitably, this is going to happen, but I feel like the solution needs to be more quickly generate-able, but still gameplay-enjoyable, content if anything, along with possibly accelerating the overall leveling experience BY making leveling across multiple classes feel more connected, rather than by just tossing on bonus EXP. I'm not saying we should bring back the fatigue system to invert the way bonus exp would basically ask us to prioritize our lead class, instead damn near forcing us to spend time on our alts, but I'd really like to stop feeling like I just unlearned almost everything I just spent 50 levels on when I hop to a new class. They 1.0 physical level partly did this, in combination with the multi-stat system—I think that's a decent start, although its previous incarnation does certainly point out some flaws.

I would prefer if all jobs get changed into classes (without replacing the current classes) and that we can use all learned skills on all classes like we did before 1.20
And THM get changed back to cone AoE DoT astral/umbral damage healer.

I personally would not prefer that. I prefer the idea of having classes as tools or paths for learning, experimentation, and coming into one's own, and jobs as goals—assuming a particular, iconic role, bringing a few different tools to it than others, perhaps, but in all ways that job. The only alternative I could see myself liking is making jobs essentially an extra skill-set, such as "Ancient Magics (Dark)", "Eikonic Manifest", <Greater White Magics>, etc., affinitive to certain classes due to their skills and weapon choices but otherwise a separate mix-and-match layer atop them.