So grinding to level 30 in the game right now IMO takes WAY to long to do, especially if you are looking at doing it with multiple characters.
In VT and DT the majority of the game is going to be taking place at end game, and the need to get everyone to 30 is rough. Might i suggest a bonus to EXP, that increases for each level 30 you have. IE, you get your first character to level 30, you then get a bonus to experience. That bonus then gets bigger once you get your second 30, then your third, then caps at 4.
I was coming here to make that suggestion exactly! I know which character I want to main but I want “alts” to fill out different teams. I always want to have the full variety of buffs by playing the missing character but leveling 4 characters to 30 sounds like a lot of work. I’m level 20 on my psyker with roughly 23 hours in, thats just over an hour per level. If I go at that same rate on release that would mean I need more than 120 hours just to level characters (not even accounting for time to equip them properly) so that I can begin to look at endgame. This is a top notch idea!