What is a "bad player" to you?

[AxlStream]

This wouldn't be because of the absence of healer dps though. You would need an actual dps class to be truly woeful to make an instance last twice as long. Likely both dps players would have to be exceptionally bad. Or auto-attacking while afk.

Or you were dying a lot. Which again wouldn't be a healer dps issue.

I think you underestimate the difference a healer makes on trash packs.