Gandalf was a 5th level magic-user, after all.
Which underscores why D&D doesn't do Tolkien well. In terms of what we see in parties in the novels... (THTABA & LOTR)
1 Angel in manifestation form, with Wiz 5 spells. No evidence he levels up.
13 dwarven fighters
1 halfling 0-level to gains thief 1 in play
3 halfling fighters. One class-changes to cavalier later on. One seems to switch to ranger or maybe druid.
1 0-level halfling who becomes a fighter
1 human non-caster ranger
1 human fighter
1 elven non-caster ranger
For NPCs, we see a fighter-cleric-illusionist, and a cleric, both of at least 5th level... remove curse and cure disease.
Note that the clerics in question have casting times in an hour or two, not a turn nor round.
The wizard, however, has casting times of a round each..
Also, the clerics may not even be clerics - they can heal, but is it really a cleric?
We see only a handful of true spell castings. Gandalf, Saruman, Galadriel, and Elrond. And Elrond is both a healer and an illusion caster...
The D&D game is much more magic-heavy than Tolkien's world. Good players with a good GM can make it work... but it's work to do it well.
ICE's game is actually going the way of "lots of magic by everyone" - but that's going too far the other way.