Im perfectly ok with planetary landings being available in 12 months, I just hope no one is expecting it to be anything special! If we consider things a bit, lets say there are only two types of planet, inhabited and uninhabited. That seems pretty simple, we could land on an uninhabited planet, explore in some buggy perhaps, survey for minerals, etc. This could be pretty much procedurally generated and there is a lot to be said for being able to fly the transition from space to ground and, assuming any of our ships (now or then) are capable of atmospheric flight, buzz canyons and dunes - sounds great. It will probably get old fast for a lot of people, but I expect in 12 months time it will strongly appeal to the majority of the player base.
The problem is with any form of inhabited planet. Lets take the Earth as a simple example, just how densely populated and built upon do you thing this planet will be in 3302? A galaxy of 400 billion stars might sound big but to be able to recreate that same (very very) basic level of interactive exploration for a planet will be a much bigger undertaking, Why travel to earth if you can only land in 2 or 3 places? what do you mean I cant fly over New York, etc. And dont think its really only a problem for Earth becuase we have some frame of rerference to the planet, the core systems and beyond are densely populated, industrial, technological. Creating any kind of depth to this experience is going to be a massive task and quite frankly they will not be doing it, I do not see how they can (but I do so hope to be proven very wrong)
Space is empty, its fairly easy to simulate, and everyone can already see that a simulation of empty space can feel, well, pretty empty at times. Empty can be good of course. But planets, worlds, nope, not seeing it.
So yes being able to land on a planet and kind of relive the mars lander moment of touch down and taking those first 'steps' on a new world will be cool, but as an 'add on' to a space sim its going to be a very shallow experience (a good one I dont doubt) with little longevity. As an expansion that provides settlements (housing), mining, manufacuring, commerce, politics - all the things we know to exist already on the populated planets we fly between - well that woudl be awesome, but that's a whole, much much, bigger game than Elite.
As for the engine being able to handle it, ok, right now it can barely handle a handful of player ships in the same place before its instancing to hell, like any MMO engine these days, lots players sharing a space is hard to handle well.