Since I don't sell code, the language I choose fits my business needs. I've used JAVA in Notes agents when needed well before Xpages was even a thing. Much like "Social", I'm dabbling in Xpages, but letting it mature, then will see if it meets my needs.
Russell Maher has an interesting post today that shows part of the xpages dilemma. He has a new pictorial showing the tools recommended to write Xpages code (DOJO, JQuery, Tomcat, etc). That's fine and dandy, but Notes has built a foundation on quick development for almost any user. That's a niche that is still largely unserved by other development platforms. We previously had a half dozen folks developing apps at the company I'm at now, because it was that easy. Now, nobody dares try to write an Xpage...their first 404 and they're left clueless.
If I'm learning additional techs just to keep developing on a locked-in IBM platform, I really need to sit down and take a hard look at the alternatives to see what advantages IBM has over the plethora of alternatives. I'm not saying there are no advantages, but it's something I need to look at.