So for the past year I've been running Tomb of Annihilation with my crew. But I've rewritten the entire book down into a 55 page word document that fits our play style. And is gear towards players over lvl 20 in 4e.
Do any of you guys rewrite stuff from modules/adventures when using so.thing form a different setting or edition?
Despite having nearly 100 pre-written hardback adventures, I have never run a single one. Though a couple of the 3rd party campaigns are absolutely fantastic and significantly better than anything I could have ever come up with. That said, I have read many of them and mine them for ideas to add to my games.
My last campaign was heavily based off of a 3rd party book, but I changed so much that even if the players read the hardback they probably wouldn't have realized it was the inspiration for the game.
I think it's completely normal (common, even) for DMs to change/tinker with campaigns. In fact, I'd be concerned if the DM didn't because published campaigns are -- A. Almost always ridiculously unbalanced (usually too easy, but there are some situations where they're TPKs if run as-written). And B. Usually far too generic and don't have enough flavor to interest any one group of players, but that's a consequence of trying to write an adventure for hundreds of thousands of players with a near-infinite number of group compositions and preferences.
As an example -- I absolutey loathe the anthology adventure books. I mean I absolutely hate them, but there are a lot of people who love them. I've never really examined why I hate them so much, but I think it's because of the fundamental way I view D&D. Some people view the game as just some characters going into a dungeon killing monsters and getting loot. Almost a videogame-like experience that's just more open-ended. And adventure anthologies line up with that style of play. However, D&D, for me, needs to be much more 'epic'. I have a hard time enjoying D&D unless the group/party are working together towards crafting their own saga/legend over the course of a long campaign.
One-shots and games of 'popcorn' D&D do almost nothing for me. I'm way too much of a whore for the drama, loss, sacrifice, revenge, and triumph that a group of players who really love the game can create.
Tl;dr
You're doing it right.