Basically for leves to be fixed they need to remove the mini-instance aspect of them. This is the reason you fail when you disconnect, that you have a timer, and that you can only do one leve at a time.

I'd much rather see leves function in a manner where you can do several at once. For example we will use Cassiopeia hollow. Let's say there is a leve to control the population of X mob, to get drops of of Y mob, and to collect Z items scattered throughout the zone.

You activate all three at once, and as you progress through the zone you can hunt for the Z items, as you find them and pick them up you will come across the Y mobs that drop the other items you need, and you will come across the X mobs that you need to kill. All of the leves can be done at once, if other people have the same leves you can join up and kill things together as you explore.

This system can be expanded into the raid instances as well... so in thousand maw instead of just going straight for this chest and that boss, you might also need to kill so many pterocs... or collect x number of bomb ash... giving everyone in the raid more goals than just killing the boss to try and get an item.

They could add npc escort, settlement defense and delivery events that correlate with leves also, "while defending so and so, kill this many of this mob." "While defending the settlement gather this many items from this specific mob."

It could even turn into a support for grinding mobs... you are this rank, you have formed a party to kill this specific mob, there is a leve that everyone can do for killing that same mob, or finding a number of items in the area that mob spawns. it would support the sp party, while also adding variety to it.