Time travel has given us many of the best stories across all the Trek series. I'd say keep it.
That's just the thing. It should not become a crutch for the writers.
But the thing is, is it really a crutch? When you look across the totality of the franchise, we have maybe four dozen actual time travel episodes out of seven-hundred plus episodes of material.
Across the Original Series, there are five time travel episodes (six if we count TAS).
I was honestly fine with time travel until ENT. I felt like the "temporal war" actually weakened the Star Trek universe. Because it means in every age, there's 29th century technology running around. It takes the mystery out of exploration for me -- you're not forging a path for future generations. Those future generations are there alongside you, making sure you are on the "proper" historical path.
Just bugs me.
Again, don't want to diminish any enjoyment you get out of time travel episodes. I just wish they would be more self-contained, and serve a specific purpose within the narrative structure of that episode. And not be the purpose. If that makes any sense.