I work as a motorcycle mechanic by trade.
When people say the big KTM is hard to work on, they are comparing it to a singer cylinder dirt bike, or maybe the BMW where most of the engine is outside the bike.
Sure, you do have to strip the tanks off on the 9x0 for most work, but once you do, everything is easy to get at.
For an oil change on my bike, I don't remove the tanks.
I suck the oil out of the tank with the oil extractor. http://www.harborfreight.com/6-1-4-q...tor-46149.html
Remove the oil drain bolt and drop the rest of the out of the bottom of the engine.
Remove the two bolts and lower down the skid plate.
I then remove the two bolts and remove the oil filter cap, keeping a big gulp cup under it to catch any extra oil.
Clean area, install new filter, reinstall cap.
Raise up skid plate and reinstall bolts.
Then add oil like normal.
The two screen are there to save the engine in case of something catastrophic going wrong, in the case of the one under the engine. And the screen in the oil tank is to prevent sucking anything down that happen to have fallen in the tank. You don't have to check and clean them every time. On my bike, I only do it when I do major service, like the valve check.
As for valve checks, once you have the tanks and carbs/throttle bodies off, access to the valves is easy. Most other street bikes make this very hard with tight clearances around the valve covers. It makes it very difficult to even see the valves, and getting in a feeler gauge near imposable. KTM does put some thought into the maintenance of their bikes.
KTM is designed different then the Japanese brands. And as such, many shops that are used to the Japanese style, have a hard time with the KTM. I maybe see 1 KTM (of any model) a month in my shop, but many Japaneses and even Chinese brands. I think that's why so many KTMs are serviced poorly and have a reputation of poor reliability.
BMW's are different too. What should be simple and obvious on a BMW, is seldom that. It's like they designed it from scratch, never looking to see how every other motorcycle on the planet does it and that it might be the way to go.
And I never understood Harley's. it's like they don't believe in using computers to design stuff. Instead they go to a well stocked hardware store and see what they can find to make a piston out of.