I want to do a replay of Skyrim, but I don't want to play the same quests again, as I'm tired of them. Is there a way to remove the quests I don't want to play? I'd probably supplement the game with community-created quests.
You could install The Choice Is Yours - this doesn't "remove" quests, but what it does do is stop them from automatically being added to your journal - if you want to undertake a quest you will have to agree to undertake it rather than it being forced upon you.
You could use console commands to complete this quests. Full list of commands you can find here, but you'll need this two: CompleteQuest to finish quest and showquesttargets to get IDs of all quests in your journal.
There is a mod to do the exact thing, it called Skyrim Quest Deleter