A recent Cochrane review found there is insufficient evidence to support or refute the common practice of removing trouble-free impacted wisdom teeth. Given this lack of evidence, the review authors propose watchful monitoring of third molar teeth for patients with no signs or symptoms of pain or discomfort associated with these teeth.
The review authors conducted a search for all randomized controlled trials (RCT) on adolescents and adults that compared the effect of prophylactic removal of asymptomatic impacted wisdom teeth with retention. Only one RCT met the inclusion criteria. This study examined the effect of removal versus retention on lower incisor crowding over 5 years and found no evidence of an effect.
I am a firm believer in this. If it ain't broke don't fix it.