If PIA wishes to surrender all premium and high yield traffic to the ME3 and TK, then sure, convert the fleet all Y and maybe even rebrand the name to "easyPIAjet" !!!
PIA has already surrendered, not just premium and high yield traffic but most international traffice to ME3 and TK, but also BA and Virgin now.
The 35 club class seats in PIA are being sold as Premium Economy now, generating around 15-20 percent extra revenue.
These same 35 seats are now being replaced by around 63 economy seasts increasing the revenue potential by 80%.
If PIA wants to improve its business class product, might be a better idea to induct newer planes like the 787-9 or A330-900.