Imran played some of the games as a specialist batsman in the last days of his career when he was about 40 years of age & few in 1983/84 when he was injured & could not bowl.Realising that he was not as good as he used to be,Imran retired in 1988 but came out of it soon on the request of Zia-ul-Haq,who was president of Pakistan then.
Only George Lohmann & Sidney Barnes have been better at their peaks than Imran Khan(ICC rankings,not my self assumption).Hence,Imran is better than any modern day bowler.Roughly,
this was his peak period.Even
thisor
this period can be considered as his peak.Its interesting that people praise Waqar for being so good in first 5 years of his career & completely ignore that Imran at his peak was better than him & for longer period of time too.