I came back from Karachi barely a couple of weeks ago. I checked with many relatives/friends (who typically vote for MQM). The responses were shocking! Almost all said: 'Let's give Imran Khan a chance now'. Only one said, 'I will vote MQM--they are our own people'. A couple of them said: 'My vote means nothing in Karachi: MQM is going to cast my vote for me even if I don't show up on the election day'.
So...before we talk about poor Haaris of Sindh being forced to vote PPP by the Waderas we need to look up on Karachi's non-Haaaris first. No denying that MQM is perhaps the biggest name in Karachi but not the way it was, say, in the 1988 elections (when I too voted MQM). MQM is not going to give up Karachi without bloodshed. And perhaps that's why Imran Khan--almost certainly being advised by veterans like Javed Hashmi and SMQ, decided to not open a front against MQM right now.
PS. PPP is not the only party with Waderas in Sindh. Not by a long shot. At least a significant number of PPP leaders from Sindh are from educated and/or middle class. The current CM Qaim Ali Shah is untainted and is also from the middle classes. Rural Sindhis are probably voting PPP because of a perceived sense of 'debt' to the wrong done to ZAB and Benazir Bhutto.