Looking forward to conduct a systematic review on a new topic which primarily contains opinions and communications. Kindly provide your valuable answer.
I suggest you do a content analysis of opinion pieces. Content analysis classically focuses on analysing communication, rather than analysing effects. So you would be focusing on what people think, how much discussion their is on a certain topic, etc., rather than finding out the effect of an intervention. To analyse interventions and effects one would do a systematic review of primary research studies (e.g. RCTs).
It is important to understand that traditional systematic reviews in bio-medical sciences are very different to content analysis, so be careful not to mix the two up.