Tom B's not everyone's favourite of course - he's certainly an acquired taste and it's arguable that the Old Forest segments would have added much to the action
narrative of the Trilogy
But then as Christopher Lee pointed out rather vigorously, cutting the Scouring of the Shire out of the ending was virtually a criminal act and failed to properly vindicate the Shire Hobbits involvement altogether...
However - this is Hollywood and Tolkien's not around to do his nut over liberties taken.
With the Hobbit I think it won't get cut quite so indiscriminately as it's largely more action-based than some parts of the LotR (being written for younger people with a limited attention span which does roughly equate to that of a 'normal' cinema audience will help a lot in this I think...
) so less likely to be skipped over quite so cavalierly. The thing with having 2 movies is that the Hobbit encompasses, but does not go into canon lore that Tolkien only made very brief references to in the book - the Siege of Dol Guldur.
This event takes place in the south of Mirkwood, a couple of hundred miles away from the track Bilbo and the dwarves took, and is what will be featured in the later parts of the films. For the film-makers it's simply a case of following Gandalf when he parts company with the dwarves after they leave the house of Beorn the skin-changer and go South to meet Elrond, Celeborn, Radagast and Saruman and push the Necromancer out of his lair. The military sequences are likely to be spectacularly heavy on the CGI as there are a lot of magic-wielders in there so it's quite a mixed feeling of anticipation and apprehension as to how much of this will be put in as Tolkien only made fairly light sketches accounting for this event, which in fact is more important lore-wise than Bilbo finding the ring in some respects
Anyway - the 3 films were successful on the whole if you can get over certain aberrations (the Scouring and ditching Glorfindel in favour of Arwen were the worst ones for me) and TBH for modern audiences trying to squeeze everything in would likely have lessened the wow factor for some of the less dynamic events, so horses for courses I suppose
I very much doubt that the Silmarillion
will be made over in my lifetime - but I live to be amazed in that respect