I think all LOTR / Hobbit sets from 1. wave will rise in future a lot, since:
1) they have had a very short production life (1.5 year for LOTR, 1 year and something for Hobbit),
2) this theme has a big fan base with ideal age for future purchases (teenage and AFOLs),
3) this theme will be never repeated in future, but the theme will be popular regardless of the existence of movies - this theme was popular even before the movies came,
4) almost every set contains exclusive figs, so if you need a complete set of main characters, you need to buy all sets.
Of course, there are some sets which will be more popular - Helms deep (big set showing an important scene), Uruk hai army (necessary for building a big army), Orthanc (biggest set), Unexpected gathering (definitely a winner of all hobbit sets, since contain many exclusive figs + iconic building with exclusive parts), but also many other sets are important for every collector - Orc Forge (good as a support for tower of Orthanc), Attack on weathertop (exclusive ringwraiths), Moria (troll and Boromir), Goblin king (goblins, exclusive wargs), Attack of the Wargs (wargs + exclusive dwarfs), Mirkwood spiders (beautiful Tauriel), Barrel escape (exclusive dwarfs). The same situation will be with the second wave - every set has exclusive figs and good point is that the TLG put many figs in every LOTR/Hobbit set contrary to other similar sets.
I also dont agree that Goblin king set has not a big potential - this set is nice detailed and contains many exlusive figs. I agree that the price is high, but if you buy it with a discount, you can expect a nice profit in future.
I believe in potential of these sets very strongly - this theme has a big fan base, the sets are well detailed, contain many figs, and most of them are exclusive and not repeated in other sets. I think these years are a golden era for investing, since there are so many other perfect sets produced during these years.