Hello,      Yes, I agree with your dentist's advice to get the opposing tooth(28) extracted as 28 could supraerupt downward as there is no 38 to stop it. Prophylactic wisdom teeth removal is a common practice in the western countries. Eruption of teeth called teething is usually associated with discomfort of moderate to severe degree . So if the diagnostic x-ray reveals the presence of adequate space for the eruption of teeth then the discomfort should be managed conservatively with medication or minimally invasive procedures . If the tooth remains asymptomatic then the possibility of development of cyst in association with the tooth is very minimal.So I would recommend wait and watch technique involving periodic evaluation of the status of the tooth rather than extraction .But the tooth opposite to the one already extracted(28) has to be removed.

It will not affect the adjacent teeth, you can get them removed prophylactically...in some western nations it's done mandatorily... Ya doc is correct if you don't get the opposite tooth removed,the upper tooth will start growing in the lower tooth's space known as supraeruption