Yeah, I was right there with my WR450. Really wanted it to work as an ADV type bike, but with 5 hour recommended oil changes, which translates to about 250 miles on main roads (5 hours at 50 mph). Even if you stretched the changes out times 5, thats still an oil change every ~1250 miles.
The problem, as I see it, is that the sump on the WR only holds 1 measley quart of oil. I believe the KTM 500 EXC is the same. Thats all well and good for a race bike, where you change the oil after every race, but not for something that you want to ride 300 to 400 miles a day for weeks. But, making the crankcases big enough for 4 or 5 quarts of oil is what gets you into these bigger ADV bike sizes.
Yeah, you could probably run the bike on one quart of oil and never change it, which about what these Aussies report doing. Treat it like your lawn mower or snow blower. But just cause you can doesnt mean that you should. Right?