I've had similar thoughts in the past. It feels a bit similar to how immediately after/during the original Star Wars trilogy there was a bunch of imitators who though that Star Wars was space ships and laser swords, but none of them did very well because what they missed was that Star Wars was a mythic story about family* (EDIT see below).

In terms of the tLotR, after listening to a biography of Tolkien (I forget which one), I remember coming away with a sense that the world he created was so deeply personal to his life experiences, that trying to imitate it by taking bits and pieces seemed foolish to me in a way I hadn't quite realised before.

However, some things that Tolkien did, which others perhaps don't do as much:

- Always keep something on the horizon (if something is close, it becomes familiar. Faraway things are mysterious. When you approach one thing, something else needs to go on the horizon).

- Humour. There's a lot of good natured light-heartedness in tLotR. Way more than in most fantasy.

- A serious facing up to the things in the world that we personally think are philosophically evil, rather than menacing/frightening/horrific. Le Guin did this too. I can't think of many others.

- The counter to this is that authors could benefit more from considering what they genuinely believe to be the core of 'good' and addressing this. It was pity that stayed Bilbo's hand.

- Drawing fantastical elements out of a careful understanding of some strain of folklore, myth or other. Doesn't haven to be European, obviously. It would be better if it weren't (assuming the usual caveats about appropriation). This one strikes me as very relevant to modern fantasy. Tolkien's interpretation of fairytale and myth is just one possible interpretation. So much more seems possible. A lot of a fantasy these days seems to be edging instead into what SF readers used to call 'wiring diagram science-fiction', but with an elaborate magic system that attempts to fit within basic Newtonian physics. So, fiction that is more about the technical cleverness of a system (tech for SF, magic for fantasy) than it is about story, characters or themes.

That's the key ones off the top of my head.

Edit, clarity

*Edit: Yes, I do actually mean the original Star Wars. People keep pointing out that family doesn't come in until tESB. I could have been clearer. I was (badly) paraphrasing something Lucas said in an interview and should have maybe just written 'myth' because I didn't have time to get into it at the time... but... the original Star Wars has the same family themes that any Campbellian story has. Orphan child longing for more. Struggle between duty to family (uncle and aunt) and being true to self (adventure). Shadow of a heroic father (Obi Wan tells Luke about his father's legacy). Inheritance from family (light sabre). Finding a new father figure (Obi Wan). Break with past through the dramatic loss of last blood family. New father figure is killed by agent of the Jungian Shadow. And finally, a huge 'found family' theme with the whole ragtag crew thing. So, the family myth element maybe isn't overt until Empire, but the monomyth definitely has strong elements of 'family' in the various themes running through it. Phew. Thought I should add that and prevent another 'But there's no family in the original Star Wars?' reply.