Even better would be if there were user-configurable "lists", whereby you could decide upfront what you want / don't want to see (like many sites do right now with NSFW content) - the default filter would be very "protective" (no porn, no violence, no gore, no hate speech) but users could turn off any or all of these "filters". The next step is the addition of user-curated "lists" / "filters" (e.g. "no democrats", "no republicans", "no vegans", "no dog lovers", ...).
All tweets containing muted words will be omitted from your timeline, or if they show up in a thread you're viewing, hidden in-place with a button to reveal. I use this feature liberally. Twitter would be unbearable without it.