I agree it mainly has to do with the Apps. I don't think Apple really had a chance to work out the kinks due to apps because I would speculate that they were nearly all submitted near the deadline of the opening of the app store. On top of that, Apple was under huge pressure to make good on the introduction when it did due to Wall Street and its stated date of committment.
Anyhow, while none of that completely justifies the sometimes-mess we now live with, we are all part of this experiment in a mobile platform with a rush of new applications. Just like the experiment with opening Mobile Me with a huge flood of people suddenly using it.
I'll bet you three things -
(1) Apple's human tech resources are straining around the clock, and
(2) These same resources are also having crashes on their own phones and know exactly what work is cut out for them and
(3) We will see regular software OS updates that nail the issues.
And I agree - fewer apps on the phone would be a good idea for a while until the initial rush to market gets updated with more-bugfree versions of their software (in progress) unencumbered by issues beyond their workaround control due to OS issues - it is the synergy of rushed apps and rushed OS that will settle out hopefully soon.
Is the iPhone the OS 9 of Phones?