In my opinion all parties are worst with no exception. However if we state some basic reasons as to why we treat them as such will be much better i.e.
PPP = Responsible for breaking Pakistan (Loss of East Pakistan); Non measurable financial destruction & corruption (Nationalization, Mis-use of quota system over merit; Mis-use of Power & Authority etc etc)
PML-N = Mutually responsible for the loss at Kargil; Height of Corruption & discrimination; Misuse of Authority & Power; Serious Financial frauds & manipulations etc etc
Jamat E Islami have least charges of corruption but weapons thing yes but I don't mind weapons as long as they are not used against your own Muslims Brothers or Civilians
MQM = Gang of killers, thugs, dacoits, Land Mafia. Seriously involved together with other forces in destroying Karachi, Hyderabad & other cities of Sindh. Although now they claim to have realized their mistakes but time will tell the true face of these thugs.
ANP = Corrupt, Mis-use of Power & Authority, Involved in Land mafia, Involved in financial scams etc etc
Jamat Islami = First Party to introduce weapons in Educational Institutions, Hypocrates, Corrupt & involved in militancy etc
JUI = Completely corrupt & baseless (Involved in hoarding & Diesel smuggling etc), Main cause of terrorism within the country; Mis-use Religion by misguiding youth about Islam etc etc.
Tehreek-e-Insaf = Not tested as yet however apparently time will tell that do they hold any depth and actions to fix the problems --> So wno't include it in the current rating as they haven't proven their worth as yet.
Correct me, if I meet some material players.
Thanks