Well, the Force is intentionally bland, at least in the Beta, as it's not the primary focus of the game. This has actually come up a few times in the past, both here (particularly in the Beta forums) and over on the d20 Radio boards.
Honestly, unless you're running an entire group of Force-users, it's probably best to not try and meddle too much with the rules for the Force.
Also, what little info you did provide is really nebulous on the downside of relying too much on the dark side of the force, something that's been a consistent feature of all prior Star Wars RPGs. Both d6 and d20 versions had a dark side score, and when you went past a certain threshold, the Force-user became an NPC villain and was retired from play.
The game already has a "tempation of the dark side" in that Force-user PCs (really the only ones that need to worry about the dark side) will have the temptation (particularly at the early stages of their adventuring career) to spend a Light Side Destiny Point to convert those Dark Side pips into usable Force Points. The only thing missing is a long term consequence for doing so, as the Destiny Ponit flip is already present as a short-term consequence. The Beta has a sidebar suggesting that Force-users that are too dark in their actions or too quick to rely on the Dark Side (i.e. spending Destiny Points in the way I just mentioned) might become Dark Side Force-users, but that's about it, and there's no measuring stick for when that fall from grace should occur (possibly with good reason).