After I traded in my '14 DL1000 for '18 DL1000 I also found that brakes were very weak. I mean, there should be no difference between '14 and '18 but there was, and it was huge. Many trips to dealer but there seemed to be nothing wrong with the bike.
Well, I know this is strange, but first step towards final solution was made one day when my bike was parked for more the two hours in heavy rain. It was still raining and I had to ride it home. Well, with pads soaked the brakes had huge impovement. WTF????
After the pads dried out, it was all bad again. So, I concluded that my pads were contaminated. And they were (and I didn't know how and why). Purchased new set of front pads and used the technique to bed them in properly.
WOW... On first use I almost went over my handlebars...
Just after that I had to do 15 days trip and bike stayed parked in garage. When I came back home and used it for the first time, both brakes, front and rear, were empty. No pressure at all. Pumped the front one and it started to work fine but the rear one was completely dead.
Went to petrol station and got DOT4 to bleed the brakes. There was so much air/bubbles that I had to use all 250ml of DOT4. After that, everything was working fine but I was completely puzzled about that air. How did it find the way in... and that much...?
One week after, I was cleaning the bike and accidentally touched bellow front left banjo bolt... and it was full of brake oil. Here it was, the answer. That is how my old pads got soaked and that was the spot where the air was getting in. Trip to the dealer, new washer and 5 minutes later all was like new. Now I have the brakes the way they were supposed to be since day one. Almost one year of difficulties to stop brand new bike.
Well, at least it's solved now.