The old ejectors don't have anything wrong with them, there's another problem in a small percentage of recent production Glocks which causes the ejection problems and the new ejectors change ejection enough to fix the problem. The cause of the problem is open to speculation.
I've tried replacing my extractor and trigger housing w/ejector and the extractor did make a small difference, but the gun still ejects erratically. From what I can see comparing the spent casings from my G23 which ejects fine and my G27 which has erratic ejection, in the G27 the extractor isn't holding the rim of the casing to the breech face so the casing is allowed to turn and drop lower before the ejector hits it. The casing pivots right and scrapes against the slide at the case mouth just below the ejection port opening, then pivots upward and the rim comes out from under the extractor claw early, then the casing bounces around in the ejection port any number of ways. The new ejector has a rearward tilt to the face of it which raises the case mouth of the casing earlier during ejection, plus the face of the ejector is taller from top to bottom so that no matter how far down the casing drops - the ejector will act on it in the same manner.
My own personal theory as to the cause is that the cut-out in the slide for the extractor is machined too far forward toward the muzzle so the extractor isn't holding the rim of the casing to the breech face. Using the same extractor in the slides of both of my guns with a spent casing that has the primer punched out and the spent casing manually pushed against the breech face, I can see that there's more of the gap between the extractor claw and breech face in the G27 slide.
I've tried different 1882(old) ejectors and .40 LCI and non-LCI extractors with the appropriate spring loaded bearings and nothing has fixed it. The non-LCI 15 degree .40 extractor and non-LCI spring loaded bearing made ejection a little bit better but ejection is still erratic.
SGT Duffman, a member of this forum, was one of the first people to receive the new 30274 9mm ejectors. He had also tried an older LCI 9mm extractor and it didn't fix the ejection, only the new ejector fixed the ejection for him. Of everyone who had the ejection problem and got the new ejector installed in their gun, 100% report that the new ejector fixed the problem.