Hi there,
I've been following this topic since nearly beginning, and what amuses me about this discussion that lasts probably already for years , is that most pesimists use the same reasons against LOTR theme repeatedly - all that about lack of vehicles, too much of epicness, too much location-oriented movies, lack of interest of kids in it etc. I think you are all shoul change the point of view of an AFOL to the point of view of average Lego customer - both parent and kid. Official sets are far different from MOCs of all of us, average buyer doesn't consider sets with those criteria, like the appriopriate scale of buildings or number of vehicles - for every example of successfull vehicle set you can find another successfull one that has equally high playability wihtout any vehicles, both in current sets and the old ones, even those from the 90's.
So when we try to guess, whether we'll get the LOTR theme or not, let's not forget, how do all the other licensed sets look like - if we think of all the simplifications and symbolic constructions of PotC, Indiana Jones, Prince of Persia, Harry Potter or SW objecs (doesn't matter what - locations, landscapes, buildings, vehicles etc.), we can see, that LOTR is no other - we could make ANY of the LOTR or Hobbit scenes (from the main plots or any additional stories, including other Tolkien books), of course it wouldn't be any close to minifig scale of original buildings, but it doesn't have to be, it's a childs toy after all. Most of the SW ships are no close to the original scale, and it's still most successfull theme in history - it doesn't matter, that UCS Death Star with minifigs is quite comic with the scenes from different movies next to each other and without any scaling at all, or that it had to take more than 5k pieces to make a proper-scale Millennium Falcon, and there are 3 other minifig versions, that are no close to this scale. In LOTR it's the same - some locations are impossible to make it in minifig scale, let's take Orthanc and Isengard for example - there have already been presented some huge, epic MOCs, but however big they were, they were still not 10m high or so, which would make a minifig-scale proper height of this tower. But does it matter? Not at all, of course, and even a comic height of, let's say, 2-storey minifig tower with balcony and characteristic top would make great Orthanc in official set, and most likely with minifigures and accessories as beautiful as in Pirates of the Caribbean. Lego doesn't pay their designers for nothing, it they need to, the will be able to make any scene, considering what's important for kids in it's story, where should be the playability, and with all the restrictions they have (in size, number of new molds, colours, permitted building techniqes etc.).
So, all in all, LOTR and Hobbit Theme isn't impossible, most of us, optimists, only give here our wishful thinking. while all the pesimists try to find any reason to say there will be no LOTR in Lego. And reasonably thinking the judgment of this matter is simple: Lego will decide what is probably best for them, in the terms of business and possible profitability, and even if it is hard to realise, it doens't mean they can't maka a profit of it. And with two Hobbit movies + renewing LOTR in 3D and all the hype they will have, they're going to be the biggest blockbusters of next two years, so it's hard to believe, that a market leader like Lego couldn't make huge profit of it. I personally believe it could beat Star Wars sales, they had their decade of s-f domination, now fantasy is coming back in books and films after all those poor years since the end of Tolkien Trillogy in cinemas, so why not in Lego.