It could worked out fine. I would have liked to see it.
At least on paper, I found the initial story and background of Yar more interesting than Crusher or Troi or Riker or LaForge.
That first season, lotta things needed to be worked out. I liked Yar, more than Riker that first year, more than some others. The actors and characters got their chance to improve, I think Yar would have been fine later on.
Worf and Yar would work fine, could have been a great team. As mentioned, the hands-on security combat guy isn't the same as the tactical guy at the weapon's station. There are two roles for them, no problem.
Also correct, all the Worf stories were about his Klingon and family stuff, rarely about his security chief duties. No conflict with Yar.
And sure it would have been possible to handle an extra character in the series. One look at DS9 shows how many MANY characters can be featured in one series AND each given substantial roles, too.
I would have liked to see Yar continue.
And yet... I don't much care for her later artificial re-appearances in whatever guise. Too stuntcast-y and ingratiating and distracting, I suppose.