Pradeep,
Clearly each of has different thoughts on the "best " camera for our purposes, but I think LS lenses are a plus for landscape shooting, since they are less likely to cause/contribute to camera shake. When locked down on a tripod, this may not be as much of an issue, but I would still opt for less movement/vibration within the camera. I am not a proponent of handheld landscape work, but if necessary (limited time, rapidly changing light, moving platform) I would opt for LS to increase the possibility of a usable image. Having said that, I admit to currently shooting LS lenses, so I am probably biased...
John
Hi John:
Frankly, I've never faced the 'shutter shock' issue in any of the digital cameras I've used in the past 15 yrs except the A7R at shutter speeds of between 1/150 to 1/250 (roughly speaking). The only LS lenses I've used have been the Phase 80, 75-150 and the 240mm so my experience is rather limited. I didn't see that they offered anything extra though, maybe it was the camera, I don't know. All I can say is that for about a fifth of the price I got a more efficient and better system with the Pentax.
As far as mirrorless is concerned, I always do my landscape imaging with the mirror up and locked so it doesn't matter either. The big advantage of mirrorless as in Sony is the size and the ability to use ANY lens with an adapter. I've even put my Canon 600 f4 MkII on it just for kicks and gotten tack sharp images. Heck, I used a Nikon 14-24 with a Nikon to Canon to Sony adapter for landscape photography in Iceland. Totally manual but the results were great.
People beat down on Sony for their UI and other issues. From where I am coming, I would say that the A7R and its successor have been revolutionary cameras in so many ways. That was one of the most innovative developments in the world of digital imaging.