Loose coupling is a tradeoff between higher design costs and lower maintenance costs. If you know you will be spending a lot of time in maintenance, then the higher design cost is amortized over the savings in maintenance. If, however, you won't be doing that much maintenance, then loose coupling is a waste of time.
In other words, if you can guarantee that maintenance will not be an issue, then couple tightly. But, personally, I've never been able to guarantee that. *shrugs*
The Perfect is the Enemy of the Good.
