We went through a similar upgrade path and my first reaction after upgrading was "Woah, these are some nasty URLs...".
Initially, we also switched to the one-pass render to have nicer URLs. But then after looking more into it, it appeared that the "?id" does more than just solve the double-sumbit problem.
Pages with Ajax components can be heavily stateful: as the user interacts with the page, you add components, remove others, etc. With the page ID in the URL parameters, you get back the page in the same state as you left it if you refresh the page (F5) or navigate to another page, then press the back button.
You lose that feature if you switch to one pass rendering since there is no way for the browser to identify which page from the page store is targeted and usually end up with another instance of the page object.
This was especially visible in "listing result" pages (pages that show a list/table of "items" with Ajax paging and filtering). On such pages with the one pass rendering, you'd often lose your search criteria or be brought back to the beginning of the results even though you had clicked "next page" a couple times.
We ended up using the "standard" rendering mechanism (not the one pass redering). URLs don't look so good but we felt the pros outweigh the cons (and the href do look OK, it's only the browser URL bar).
Another concern was the "crawlability" of our site. In order not to have the the 302s or the "url?id" impacting the Google index we added the following code in our Wicket application init method to force one-pass render for the Google Bot:
setPageRendererProvider(new IPageRendererProvider() {
@Override
public PageRenderer get(RenderPageRequestHandler handler) {
return new WebPageRenderer(handler) {
@Override
protected boolean isOnePassRender() {
// To avoid 302s with Google Bot and have good SEO.
String userAgent = ((HttpServletRequest) RequestCycle.get().getRequest().getContainerRequest()).getHeader("User-Agent");
if (StringUtils.contains(userAgent, "Googlebot")) {
return true;
} else {
return super.isOnePassRender();
}
}
};
}
});