It isn't very difficult to understand: people want ED to be more than a spaceship game. People have wanted that for thirty years, including David Braben. I am not sure what is so puzzling about people wanting that. You don't have to agree, but to not understand it...
Well to clarify, it's not that I do not understand the desire at all. Being able to go anywhere is an obvious bonus for a game like ED. But for the amount of Dev legwork required when the game is already such a mess of unfinished features and bugs while in space, the core of the game , . . . I fail to understand how anyone would want it now. I've gotten 4 people into ED in the year I have been playing. 3 dropped out in a matter of weeks because of undercooked features and bugs that made ED not worth their time. They never came close to landing on a planet, and their issue never was lack of tutorials and whatnot that FDev is currently burning their time on.
So, would landing on atmospheric planets be cool? Sure. Would it be cool if we got landable atmospheric planets when new players usually can't stomach the bugs/problems long enough to land on said planets? Eh, I think it's a bad use of dev time currently.