I was thinking about it too. I believe England, SA, NZ or Australia will not tour anytime before 2030 that is if things change drastically , could be longer too.
India being the rich board and emergence of IPL, along with growing Indo-Pak tensions will not tour either.
So that leaves SL, Zim, WI, Bangladesh.
SL might not be comfortable with touring first because they were the last team to visit who were directly attacked.
Zimbabwe could be given some incentives and their fears can be bought but they coming to Pakistan for a couple of T20s won't change much to convince stronger teams.
West Indies primary Cricketers play in T20 leagues all around the world so it's very unlikely they will give up everything to risk a tour to Pakistan.
Bangladesh : Board that is doing well these days but they are hesitant to tour first and question whether lives of their players is any less than players of Western Nations.
All in all, I don't see any teams touring Pakistan unless there is a period of 5-6 years of constant stabliltiy, negligible blasts, negligible terrorism, no Army Operations, stable government etc which may convince a semi decent team to take the first at step and others will follow suit.
