The WR is a very impressive bike. ....and having owned/ridden/raced my last 250 over 17 years ago, and having had nothing but big-bores since, for me it's hard to go backwards in HP and torque. Note that our WR is the girl's DS - I have a Y2K 640 KTM LC4-E, so the WR is not my primary mount.
I did however get an opportunity to put it through it's paces out in the Mojave on a pretty rough, wide-open road shifting between 5th and 6th and literally launching it off 70 MPH crests, it never looked back. Wasn't even breathing hard, and neither was I. Enter long, sandy whoops and while the suspension was completely satisfactory, my 200 (plus) mindset was searching for (instant) acceleration ( again, what I'm use to )
We rarely get (read: "I rarely get the girl" ) into extremely radical spots, but I'd trade it hands-down for the (My) KTM in rough single track.
Like everything else related to dual-sports, (IMO) they all leave something to be desired - Which maybe true with all bikes in general. < Frankly I can't stand not having a kick-starter; Short drive I realize, but it drives me nuts ! >
Having said all that, it's something I'm just probably use to, and my riding style has adapted accordingly.
If you prefer a wrist full and you ride the EXC, you won't look twice at the WR. It (The KTM) is one fine machine. However, as noted, you'll spend more time and money on it.
Given saddle time I think even the harshest critic (i.e. myself) would be more than ecstatic with the WR.
Either way, forget the KLX (it hasn't a chance of comparison from all I've heard) and put the KLR up for sale now ! Quick !