We all hate Al Saud, i have met people who follow a school of thought that is closer to them, but still hate them. But let's think realistically, yes if we join them there can be some rift between our people, Shia-Sunni, yes Iran will be pissed off. But don't we have that rift already and we are in no love relationship with Iran either.
In 1991 when Saddam attacked Kuwait, we had an awesome opportunity that was missed by Gen Baig. We could have moved in and stopped Saddam with the help of Saudia, GCC and other Muslim countries and that too using the money of Saudia and Kuwait, each paid 9 Billion USD to USA.
Think just how different this world would have been, no US forces in KSA so OBL would have no justification for Al-Qaida.
We could have had a whole corps equipped and paid by the Saudis stationed in KSA and Gulf, which would have acted as our reserves in case things flare up at our eastern border. More jobs for Pakistanis in KSA and Gulf, oil at deferred payments if not free, and also some say in these countries relationship with our eastern neighbor.
I won't call this an opportunity of the same magnitude, but an opportunity nevertheless. KSA is pretty isolated right now,with US having not much interest in ME because of the discovery of the shale gas and pro-Iran regimes coming to power in the region (Iraq, Yemen, Assad don't seem to be going anywhere either). They are scared and won't even hesitate asking for help from even the Israelis if need be, so why not us.
Yes i agree that one should only fight its own wars, but wars are fought to serve the interest of your country, US soldiers fighting in Desert Storm had no love for liberating Kuwait or protecting KSA, they were serving the interest of their nation and i see economic and strategic interest of Pakistan can be served if we can use KSA's insecurity the right way.