So I've come to know that my Nexus 5 is D820 model, which as far as I know, won't support the LTE band being offered by both Warid & Zong. Since I've been on Warid 's postpaid for a long time now, this certainly left a bad aftertaste that I won't be able to utilize 4G/ LTE. Either I switch to another phone (very unlikely) given how impressive Nexus 5 truly is, or I switch to another Network. Even though I don't really feel the need to get 3G, since PTCL's 8Mbps is going along nicely, I wouldn't mind giving a try to 3G because the coverage has been pretty inefficient in my area from all networks. Only Telenor seems to be offering blanket coverage in my area, though I've never given a try to Telenor's service, nor am I a fan of their auto call-dropping practice that I've heard from most of my colleagues. Ditching Warid's network is not an option, given how reliable and good their service has been lately.
I wish the phone I had bought would've been D821 model, but alas I wasn't aware of this at the time of purchase