Star Wars d20 works fine, it does the job.
Watering down just creates problems, take a look at power attack.
In Star Wars d20 that is a pre-requisite to the cleave feat, the cleave feat allows in the case you kill a enemy to make a attack on another enemy close by, its a good feat.
Of course in Star Wars d20 you dont get the "spell" force powers, things are handled completly diferent and you dont get a mana bar either, force takes vitality points