There will be an update, or should I say replacement, for the XR400. I do suspect that Honda will knock a good bit off of the power. XR's are a much bigger seller than the Yamaha WR series, and Honda doesn't want to scare anybody.
But, There will be a water-cooled, aluminum framed 450 XR in the next couple of years.
My riding group has the same question. For the CA market, Honda will have to follow the XR650R process to get it green stickered. This likely means a restrictive exhaust/intake manifold, lean jetting and probably a smog pump. Hopefully, it can be overcome with a "hop-up" kit and some afternarket goodies. The real question for us is whether it will be a suitable enduro/dual sport.
I've been debating a new bike lately and have been wondering the same thing. If their weight/power/handling claims prove true and they can provide a bike with lights and the ability to be street titled without much hassle I'm there. Are you listening Honda? Otherwise it's Yam or KTM.
My guess is that the aftermarket will quickly make available all the enduro parts you could ever want to make your own super 'CXR'. But the bike's limited supply and high cost of an enduro conversion will make it pretty rare out on the trails.
My bet is you'll see conversions on the trail a long time before Honda ever gets around to building their own.
I just converted my XR600 for about $100 not including tires. I don't want to spend $400-$450 for a kit plus Stator work if needed. It's a lot easier to just buy something else convert it and still spend less. Pretty soon Honda is going to be completely out of the 200/250/400 enduro market if they don't respond to the advances made by other manufacturers in these areas. I hope it doesn't come to that however as I have always bought and never been failed by any of their bikes.