I think the set is more concerned with giving us recognizable minifigures than it is movie accuracy. Thorin and Legolas could have been replaced with an arbitrary Iron Hill Dwarf and an arbitrary elf, but I would think kids would rather play with figures they recognize. And Legolas and Thorin were a lot more prominent than any other dwarf or elf in that movie. Personally I find this set disappointing. Maybe it's because I'm not the target audience, but I actually would have preferred an arbitrary elf, if only in order to get that Mirkwood Elf armor in minifigure form which would have been glorious. I also don't really like the ruins of Dale. I get that they're supposed to be, well, ruined, but I don't really feel like the structure captures the city's architecture that well. If they had ditched the ballista and beefed up the section of Dale I think it would have been a much more appealing set. That set, a set designed to depict the Battle of the Five Armies was always going to be difficult. In the film there was too much fighting going on too many locations, some of which were nothing more than a flat plain which would have been quite dull in a LEGO set. So I think, all complaints aside, the set designers made the right call in focussing on Dale and including the minifigures they did.