To be fair though, most of those that seem most hairy are not inherent problems in the platform, but a question of having people with the right know-how.
Oh, I don't disagree that knowledge solves many of the problems. But with the fast pace of change on this front (no end in sight) and the fragmentation of front-end browser SDKs, once you become an expert... it's time to upgrade or change SDKs, time to get a new job (same thing), someone you're working with gets replaced, some new browser or platform comes along, etc. Learning curve and ease of use are important to me in a rapidly evolving and demanding environment, and most people over the age of 30 can't be bothered to spend all the time needed to stay an expert (hard to blame them).
Like I said, a standard browser helps quite a bit, but I can't help but think back to browser upgrades which have broken key components of web apps. Which (if it's your own product) may then require you to update your front end SDK... oh, and did you see the readme about how they recommend a new version of Eclipse and require a JDK update? And then we'll have to fix any new issues, re-test... oh is that a classloader conflict? *kills self* (I realize this is a contrived example, but these things do happen and the unplanned O&M surprises are not fun.)
I was focusing (above) on the negative issues since they seem rarely discussed. Or maybe I'm just a grinch.
But I agree that the issues are in no way insurmountable. They're solved all the time. A big issue I have is that they're solved all the time. Over and over again. :) Then again, maybe this is what keeps us all employed, so I should just shut up now...