Two things.
1: Player has a choice. Thematically, they are not Jedi, and they shouldnt be dependent on the force. Powers should be far less than that of a Jedi or Sith. Allowing free reins on use of dark side points though, makes them very power oriented. Some are saying that I am wasting their XP, but that is not true. Their powers work fine, and they can do far more than the average person can hope to do, but they may need to take their time if they dont want the effects of dark side. Most of a tree isnt Powers, and the Power tree is very inexpensive for what it does. You are trying to make it sound like they are getting screwed. They arent, they may not be lifting Y fighters out of a swamp bed, but there is plenty they can do, especially when they get the not so uncommon two light force points.
2, Dark side is suppose to be dark. The person who says this goes against star wars theme, doesnt know star wars theme.
My mechanic had these force adept/exiles using force powers at about the amount they should be using them. Not throwing things in a firefight of course, like some yoda challenger... But getting the security rod from the distracted trooper, sliding a discarded blaster rifle towards a team mate who is out and holed down, lifting a team mate up an elevator shaft... All things that you can take your time to do, spending a turn or two if necessary to get the right roll on the dice. It "feels" right in every thematic way possible, both the darkness and mis perceptions, and the level of power such an exile/adept would have.
I realize that anything new, especially when it flies in the face of what you are use to, will be met with aggression and debate. As such, I wont go defending this sensible way of handling the dark side mechanics. The purpose is already served, ideas for people who, like me, dont think dark side should be so useful without the well known thematic costs. The only people screwed by this sort of gaming, are ones who expect their Force powers to be powerful and that dark side shouldnt be an issue. That is why it is important that players know in advance, which mine did, that dark side will have strong thematic effects just like in the novels and movies.