Actually if you look at it closely PMLN went for rural Sindh while PTI tried to woo urban Sindh (Karachi specifically). PMLN for their part allied themselves with Sindhi nationalists, created an issue of new metropolitan legislation (this clearly meant that they have given up on Karachi, this issue was polarizing) they then 'influenced' the nationalist strikes and dragged them into mainstream. From their point of view it makes perfect sense, their main opponent is PPP, by harming its vote bank in rural Sindh PMLN will deprive PPP of Sindh card and put it into defensive. PPP won't be able to ignore rural Sindh which means they will remain busy till elections even if they don't get much of a dent in vote bank. PMLN has been successful so far, just look how much media coverage is being given to Sindhi nationalists and they have (for the time being) broken PPP spell in rural Sindh.
PTI on the other hand went for Urban Sindh specifically Karachi. They were betting on the fact that they can woo educated segment plus they can attract voters from MQM and ANP. An alliance with JI with these votes could have gotten them a good representation in Karachi. That is why IK remained silent on metropolitan issue, he didn't want to offend Karachiites who are in favor of that legislation. Thats why PTI ignored a golden chance to hit on PPP even when dharnas are right up their ally. But here lies the problem, society is fragmented. IK might say there is no right or left but on ground there is. Muhajirs are the most educated and open minded segment of Pk, Ik can't woo both liberal and rightist (pro taliban) voters at the same time. His gains in KPK (which again are based one exploitation of Pushtoon sentiment which believes Pk establishment has double crossed them) will effect his vote-bank in Karachi. On top of it when he had lost Sindhi nationlists he suddenly makes some noise in their favor, utterly senseless as PMLN has already tapped that segment and it has no political benefit for PTI it will just alienate Karachiites. I don;t know how IK leads himself into these dead ends
. Look at South Punjab any fool knows that if you rub that issue too much you will offend central Punjab, that is why PPP is focusing on southern Punjab and has almost given up on northern/ central Punjab. How much space will be left for PTI in presence of PPP in Southern Punjab? PMLN has taken the position of administrative units and removed itself from this mess (which may hurt them) IK is still unsure. His onslaught on PMLN has all the potential of translating itself to Punjab vs All. I'm amused why PMLN has not magnified that aspect.
MQM very interestingly also came up with the slogan "Quaid ka Pakistan ya Taliban ka Pakistan" this hits PTI/ JI not ANP which is secular nationalist, which means they also consider PTI/ JI to be a threat.
In anycase thats my read on the current scenario, please let me know if you find it useful, now I can sleep easy