The pakistani all rounders are the key.
Afridi, Malik, Razzaq, Akmal are all very very good all rounders. Malik has the potential to be in the top 5 in the world, IMO afridi already is (his test stats are better than Flintoff's) and on recent form, his ODI and test averages have vastly improved. Razzaq has been a little inconsistent lately, but is still a force to be reckoned with, and Akmals batting has improved out of sight lately.
Add to that, The class of Mohammed Yousuf, the Brilliance of Inzamam Ul Haq, and the flair of Shoaib Akhtar, and this is one damn powerful one day unit. In test matches, Danish Kaneria adds even more.
Pakistan have the potential to be number 2 in the world in both facets of the game. infact, in ODI's, i'd put them there already.
They have shown enough, to suggest they can be number one in the world for ODI's, but have yet to reach those heights. Next World Cup will be good