Hi there, folks,
For such a lore heavy game as Grim Dawn, I feel like there’s one important piece missing - a proper justification for the classes available to the player. It seems that you just… hit level 1, and become this or that class, and at 10 get to add another one - very little, if any reason or rhyme behind it. I know that this is somewhat due to the fact that you don’t start with pre-selected classes like in Diablo, but I think there are ways to work around that.
I feel like there should be some explanation as to why all of a sudden you get access to all this power and skills.
My suggestion would be:
Right at the start of the game, you get a quest to talk to the spirit guide, who hands you your diary, which contains hints about your past. The diary, however, is missing pages and the remaining text is incomplete.
The diary is full of clues about your past life - including your profession or craft, which you must have had when you were possessed - but due to the aetherial entering your mind, you memory is cloudy.
You only get to make full sense of your past and choose your first class once you’ve done some killing and gained enough experience, which brings back the memories of your past life and your profession.
So essentially, you get to become a necromancer at level one, because you were a necromancer originally. The aetherial possession has scrambled your mind, and it will take some practice before you become as skilled in your craft as you were before - which would justify having to level up before gaining access to upper level skills.
A random text could pop up once you reach level one, something on the lines of: “Dealing with these monstrosities, you feel like you’ve done this before. The scent of blood, the rush of adrenaline and arcane power are nothing new to you. Bit by bit, the past, contained within your diary starts making sense, and the missing pieces are filled with every new encounter. Your past comes back you, and you remember who you are.”
As for level 10 second class choosing, my suggestion would be to introduce a speculation that the aetherial which possessed you had possessed others before, and, despite the fact that it was exorcised, an imprint of its past vessel still remains in your mind.
Possession has damaged your skill in your original profession, but has given you access to another one, by exposing you to the minds (or one powerful mind) that the aetherial had possessed before picking you as a vessel.
This could as well be revealed to you by the spirit guide. For example, by introducing an additional dialogue option once you hit level 10, something on the lines of you having nightmares and bad dreams recently. The dreams reveal a life completely alien and unknown to you. The guide then offers to perform a hypnotic ritual to find out the reasons behind this - maybe after you complete a certain quest to get an item necessary for the ritual - and gives you the answer: possession has exposed your mind to the aetherial’s past, and has given you access to a different power.
It could be reversed, so that you get you choose your first class because of possession, and remember your original one as you progress further.
I know this is would be a minor addition, but I feel like it would help make the lore and the story feel more complete, and your powers more justified and story driven.
Let me know what you guys think 
