Hmm.. things the D&D Movie did good just off the top of my head.
1) A world where magic, monsters, and elves/dwarves/etc exists.
2) A charming and well-played good-hearted rogue.
3) A bookish and hot "low-level mage" who gets won over by said rogue's charms.
4) Showing the creation and testing of a magic item. How many movies have done this, again?
5) Dragon battles.
6) The inklings of a look into the relationship between a high level mage and a high-level fighter doing his bidding. If you think about it, it does explain fighters being at the beck and call of wizards, sometimes against their wishes.
7) Animated, talking skeletons. You could put talking skwlwtons in My Dinner with Andre, and I'd watch.
8) Dragon battles.
9) The thief maze. People keep not getting that what was shown on screen would have represented PART of the challenge. If you assume that it wasn;t just a 3-room-and-out "deadly" maze, it should make that part work for you.
10) The wall that the mages put up against the fire-blasts from the dragons. DAMN that was awesome to see!
11) Great looking fantasy creatures that looked like Beholders. I don't care if they had "Beholders" fetching coffee - I just thought it rocked seeing them on screen.
Interesting side note - I didn't see anyone up in arms over using a Beholder-ish creature in Big Trouble in Little China - people just say "Cool creature".
Just because they name the movie Dungeons and Dragons makes the frames of film that have the creature in them less cool?
12) Frickin DRAGON BATTLES.
Just because it's a D&D movie and they aren't "By-the-book D&D Dragons" makes you ignore the fact that they had a battle with dragons over a fantastical city with in-air bites and claws and flame-breathing??!
That's off the top of my head....