The future war (if it ever occurs) will be very much shorter than the Gulf War. The Iraqi armed forces are a shadow of their former selves and even in 1991 they surrendered in a matter of days. The US plan to lob 300-400 Tomahawks per day onto there will positions will break them, and fast.
The main threat is the Scud. However, I read in the Times the other week that the US/UK believe that only 20-30 missiles exist. I would put money on these being launched against Israel (Saddam going out with a bang so to speak) rather than at a fellow Arab state, no matter how much the latter is allied to the United States. In any case, the Patriot anti-missle system is installed in Bahrain (see the GDN last week) and is vastly superior to the version operating in 1991 (when it had been hastily converted from an anti-aircraft to an anti-missle system with a corresponding drop in effectiveness).
As for domestic political disturbances, these are unlikely to prove much of a threat. The Security Service in Bahrain has always run a very tight ship. It may have been 'relaxed' due to democratic reforms last year but after the disturbances over New Year's, I would imagine was now operating at full strength - especially with a war coming. Westerners will be protected against any violence, that you can be assured of. With Bahrain's new focus on tourism, Westerners are prized assets and the King has made it clear that he will not tolerate anything that damages Bahrain's international reputation.
If it's anything like the first war, the Airport will be closed for a few days, aircraft rerouted and a lot of young, tough American men wandering about. But it's going to be over very quickly indeed.