Is she? Or is this just today's hot take? I think some people confuse media attention with effectiveness. Some of the most effective legislators fly beneath the radar, quietly working with others to craft legislation that gets passed into law. In Congress they distinguish between show horses and work horses.
None of these frosh Democrats have done so yet. They are like the 1995 frosh Republicans with their Contract with America. They celebrated when they passed it on the House, and thought they'd changed everything, but only one small portion ever became law.
Some of those frosh GOPers went on to become effective work horses, and some of these frosh Dems likely will, too. But so far the ones getting the most notice, Omar, Tlaib, and AOC, have not proved they're more than show horses.