More late thoughts to add to my first post.
Money could be grinded at Armax arena, no problem, especially for those who played ME3 mutiplayer.
The problem is, for the best experience, all possible characters should be acquired, meaning Citadel DLC is best played very late in the game, which makes money grind almost pointless - not much missions left to experiment with weapons.
To me, the best option is to increase the amount of money player collects trough the game. In this case it would be possible to collect items steadily, and Citadel shooting range would be useful again.
