I get the interest of caracter progress when you’re starting the game, it help you learn through soldier and veterant mode and you start with the easy carreer before going to the hardest one once you get the gest.
But having to grind each caracters one by one quickly get pretty stale, especially when playing with other and having to “force” them to get back in vet so you can grind your new heros through lvl you already know everything about so you can have the guy strong enought to get back to legend to get decent stuff.
give caracter an xp multiplicator based on how many caracters you have that are of an higher level.
for exemple if I have sienna, bardin and krub lvl 35, kerilian lvl 15 and saltz lvl 2.
I will have xp time five on satlz until lvl 15 then time four until lvl 35.
Value can be tweaked of course but I feel like this would really make trying a new caracter a far better experience.