About 3 weeks ago, I put the same tire on my 08.
I have always been a fan of the Michelin LTX M/S and of the LTX M/S2 and have used both on several vehicles. Both tires rode quite well for me and I always loved the soft ride on them. The side walls flexed well and the rubber/tread absorbed the imperfections or rocks in the road.
Three weeks ago, I went to put on the LTX M/S2 and found out Michelin had discontinued them. The Defender LTX M/S was available, so I decided to try those.
I was already aware of them and had read about the difference and what they did to improve the tire.
IMO, the Defender LTX M/S does not have the same ride quality I experienced with the other Michelins I used.
I feel the bumps more, it's a harder ride, the sidewalls don't flex as much and the tread/rubber is harder. I expected the tires would ride differently then what I had experienced with the LTX M/S and LTX M/S2 but the Defender LTX M/S is not an improvement to me. They may get more tread life out of them due to the improvements, but the ride quality is not the same; it is a harsher ride. I do like the wider rain channels and the extra sipping however.
I can see where you are at. If you disappointed in the tires, then try another tire. I may as well.
Make sure you tire pressure is correct.