There is a reason why all-rounders are rare. It is because it takes a hell of a lot of work and talent to be good at both batting and bowling.
Specialist players are at a disadvantage when compared to all-rounders and that is how it should be. A player like Kallis is easily more valuable than a player like Dravid. Similarly, Imran Khan is a more valuable player than Sachin Tendulker.
Of course, the players being compared should be of comparable skill in one format for the secondary skills to come into play. Comparing Warne or Inzi with Afridi is silly.
No I don't agree that specialist players should be at a disadvantage. If that's the case than the top 10 greatest players of all time should all be all-rounders, and even today the best cricketers in the world should be all-rounders not batsmen or bowlers.
Imran is one of the greatest Test bowlers the game has ever seen. He is certainly in the top 5 of all time, but in ODIs, there are several bowlers ahead of him. On the other hand, Tendulkar is the only batsman who is a certainty when it comes to top 5 in both formats.
There is a good reason why Tendulkar makes more all-time XIs than Imran, even if we ignore the Indian or the Pakistani bias. Simply because his batting was better than Imran's bowling, and there aren't many names that you would ahead of him in your batting lineup but there are several bowlers such as Wasim, McGrath, Marshall, Lillee, Hadlee etc. that make these all-time XIs ahead of Imran.
Mostly, Imran doesn't even make an all-time XI ahead of Sobers, and that is because when you compare him to the likes of Sobers, Botham or even Miller, he hasn't influenced/impacted many matches and series with both bat and ball.
Imran was an ATG bowler but his batting is overstated on PP; he doesn't make any top team based on his batting alone, and that 50 average of his during the last few years of his career is misleading because of not out inflation, and more importantly, his run production was not comparable to other batsmen with 50+ averages.
As an all-rounder, Imran is the reverse of Kallis. An ATG bowler and a decent, serviceable batsman who won't make most teams without his bowling. Just like how Kallis was an ATG batsman but won't make most teams due to his bowling alone. In their peaks, Sobers, Botham and Miller would have walked into any team either as a batsman or as a bowler. As a bowler, Imran is better than every ATG all-rounder in history except for maybe Hadlee, but he was a better batsman than the latter only.
Imran is the best Asian all-rounder of all time and certainly among the top 10 cricketers in history. In addition, he is also the most influential cricketer that Pakistan has ever produced, and also a genuinely great captain who would most likely captain a team if he gets into the XI. That is more than enough praise and adulation, but let's not make him what he is not - he is not a bigger player than Tendulkar, and he is not the greatest all-rounder of all time. That is part of the PP, green-tinted narrative and doesn't exist outside the scope of this forum.