Who says areas of non Muhajir have no voice?? You are dragging ethnicity into matters to fulfill your own unpure desires! Do you really think issues faced by muhajir and non muhajir in Karachi are any different?? DO you think issues faced by Pathans and Muhajirs in Orangi are different? Or issues faced by any community living in Karachi are any different?
When MQM raises its voice for Karachi, it raises it for all communities based in Karachi, all ethnicities, all nationalities
Now to your question, MQM has 2 Sindhi MPAs and 1 MNA, as well as a Baloch MPA from Lyari. The areas MPA is supposed to raise voice for all people living his constituency regardless of ethnicity. The development work done in Mustufa Kamals time benefited all people living in Karachi regardless of ethnicity
Maybe you should stop looking at Karachi through your ethnic prism. You will live longer. Honest advise.