I LOVE what they've done. Firstly, the Dark Side is more tempting - and this is handled via the Force Dice. There are actually more Dark Side faces on it than light side faces, but the light side faces have more points on them (generally). So the Dark Side is easy, presents itself often… and is seductive to use. But the light side is stronger.
Using Dark Side Points to fuel your force powers removes light side destiny points from the pool, turning them to dark side points for the GM. From a narrative perspective, the Dark Side is exacting it's toll… (and if there are no light side points in the destiny point pool, then the force user suffers strain.)
As for long-term effects of calling upon the Dark Side, what that means for the character, and whether they "fall" and become NPCs… the book very clearly says this is ENTIRELY up to the GM. IMHO, having played every Star Wars system ever published, this is bold - and much needed. Saga Edition, for example, turned it into a math game. "Oooh! I have 4 DSPs… better save up 4 Force Points to atone…" and this required the GM to house-rule things anyway to nerf such silliness. But when you no longer codify it, and leave it unwritten and entirely up to the GM… then things are as they should be!!
Just my opinion. For me, it's a welcome change.