Who knows what any given technology's long-term problems will be in software? What is "long-term" in software? 2 years? 10 years? PHP, RoR and Python have significant problems as well (just different ones), so I'd say it's not possible to predict what's going to happen long-term.
I doubt that any single framework is going to be able to solve a "barrier to entry" kind of problem. Having only cursory knowledge of Struts 2, I don't think it can begin to do that. It's not significantly simpler than some of the other available frameworks (I'll grant that it is a lot simpler than
JSF, but that's not saying much).
But, honestly, what's harder about
JSP than about PHP? Of course, many commonly used PHP techniques are frowned upon in JSP because better and more powerful approaches -from a SW engineering point of view- are available. And, yes, it takes time to learn about those, and possibly makes for somewhat slower development (but possibly for better maintenance, which generally is the larger part of development). But writing basic JSPs has about the same learning curve as writing basic PHPs.
[ September 12, 2008: Message edited by: Ulf Dittmer ]