We don't need to indulge in hypotheticals or "what ifs" to test this. As
@Flair Hay said, it is staring in our face, this has been posted so many times that people are probably tired of posting but we conducted this experiment with the exact same players last season when Connor was injured
With the lines as
Ehlers - Scheifele - Vilardi
Perfetti - Names - Iafallo
the Jets record was 13 - 2 - 2 with a points % of .824 with a +27 5v5 goal differential and elite fancy stats.
Now unless you think Connor is a worse player than Iafallo or Perfetti, there is no reason to assume that it will have a net worse affect.
If the Jets had stuck with ESV, the Jets would be a President's trophy team with a better final record. Not even a question in my head.
I don't like the "40+ goal scorer being 'forced' to play with Names" line of thinking. Now you are prioritizing Connor's personal stats over the team. Connor scoring 30 on a 2nd line while the Jets have a better win loss record is much more desirable than Connor scoring 40 when the team is overall worse.