Pre-50 alt job leveling is a slog.

[Griffmstr]

This game has so many different systems and things that offer experience but they don't seem to be used to their maximum potential.
Lets take the hunting log for example, at first ticking off the beasts in the log is a quick way to gain several levels. Doing the first set including your intro quests almost guarantees you level 10 and then set two unlocks. However once you hit 20, doing the entire set of new hunting log isn't even enough to gain a single level.
Fates are much the same too, and the challenge log. At first doing a few fates and completing the log could easily gain you several levels. However once again around 20 you'd be lucky to gain a level at all.
Battlecraft leves are notoriously lackluster for experience gained to the point where they even stopped being supported in the more current expansions only offering fieldcraft and crafting leves.

I see a lot of mog station gear offer experience bonus of 30% when worn as a set. That is fine and all but the gear usually has very minimal stats and for melee or tank users you really run a risk of gimping yourself just to gain a boost of exp.
So my suggestion would be, once you finish the current expansions main story quest a vendor unlocks that allows you to buy gear with poetics that boosts experience gained until level 50. After level 50 the gear is useless. Maybe there could be 4 different sets or something so one for tanks, healers, casters, and physical. Maybe the stats and armor will scale much the same way max level gear scales when synced in a dungeon.

The bigger thing would be not only experience gained increase like the current mog station armor, but give boosts to other forms of experience gained as well. Maybe completing a battlecraft leve at the highest difficulty with the best reward will give you 5x more experience or something. Giving people a reason to use a system that is mostly ignored. Maybe have it so doing fates of a comparative level sometimes give triple experience. Completing 3 challenge log entries gives double exp. The list could go on and on. Instead of just giving you experience to grind more dungeons let the exp boost be for things outside of dungeon grinds to gain experience.
This might sound overpowered and too good to be true but considering it only works until 50 I think it is a valid alternative than simply paying to instantly level something to 70 and not getting the personal experience of knowing a class by leveling it up normally.

[Seraphor]

EXP gains aren't well balanced in general. While leveling an alt job is a slog, you gain way too much from the MSQ.

I'd just reduce general EXP gains by about 20-30%, including MSQ rewards, and then increase the Armoury Bonus to counter this, maybe by +50%, to make leveling alt jobs easier.

You're expected to try out different jobs, and leveling is by no means a huge hurdle to overcome, but it could put off new players who end up disliking their first chosen job.

[MistakeNot]

EXP gains aren't well balanced in general. While leveling an alt job is a slog, you gain way too much from the MSQ.

I'd just reduce general EXP gains by about 20-30%, including MSQ rewards, and then increase the Armoury Bonus to counter this, maybe by +50%, to make leveling alt jobs easier.

You're expected to try out different jobs, and leveling is by no means a huge hurdle to overcome, but it could put off new players who end up disliking their first chosen job.

In general you get enough EXP to level up two jobs in parallell. It is only when you get to your third (and fourth etc) job that it can become a bit of a slog - but even then it is not hard at all to level up a job unless you are in a hurry.
Hunt log, FATEs, daily roulettes, Palace of the Dead, Challenge log - together they give a lot of EXP.

[sleepy-bear]

The exp you get from battlecraft leves is particularly bad. I wish those would be buffed a little, but they seem to have been abandoned altogether as of SB.

[SentinelBasch]

My favorite way of leveling alts to 50 is through command missions. They cost seals but you will get all the treasure in dungeons that you can trade in to get many of those seals back.

You already get the xp bonus for having a higher level toon, and can take out all the enemies in the dungeon for max xp.

It is slower at first, but as tactics are unlocked and raised, you can pump up your squad's offense significantly.

There is a period before and after Brayflox that I still group with other players due to the wide gap, but apart from that, the xp is pretty nice. Much faster than fates or leves in my experience and is also great for sharpening new skills before you jump in the new class with other people.