This isnt a comment on the house rule at hand, but more just general: I've always wondered why some people are so intent on stopping the stroll to paragon-ness. It's not like you get a hundred experience and a crate full of puppies or something. A little bit extra strain and an additional Destiny Point isn't going to move the needle that much, as far as game breakers go.
Is this more of a big deal than I'm seeing?
It doesn't bother me mechanically. It bothers me because I feel it's stupid. I think Light Side Paragon is something you should work to achieve bit by bit by making the right choices.
That's why I proposed using different dice based on the player's actions.
Then make the players work at it. Give them difficult choices. Through ravines and cliffs and other obsticals in the path to becoming paragon. You do not need to change the mechanic to do so,