As always, the answer is dependent on if you like what it offers. For some, it's a half day park. For others, like me, it could be a 3 day park...and I'm not a Star Wars nut (I like it, don't love it). Does your 6 year old like thrill rides and is she tall enough? If so, RnR and ToT are awesome!! Do you like shows? There are plenty to see. TSMM is a blast, I could ride it 6 times in a row. Star Tours is fun, even if you're not a fan. One Mans Dream is worth a visit.
So yes, without a doubt it's worth two days, IMO, especially if you have 10 days in the parks. Even without RnR and ToT if you skip them...and I recommend doing them.