I would agree that pleasure is important too, but I think I'd place a higher disvalue on suffering than I place value on pleasure. I definitely don't think that a world without suffering would necessarily be a state of hedonic neutral, or result in meaninglessness. However, I would also be one to bite the bullet and say that a Melba toast world with general pleasantness but no true joy or wonder would be preferable to a world with widespread extreme suffering (at least on the scale it exists on today) if that was necessary. I'd also say the ideal version of a Type 3 wouldn't have had to, since I would agree that pleasure doesn't depend on suffering to exist. I think the strongest drawback would be the one mentioned in the comment below: the risk of forgetting suffering too soon. Empathy isn't our strong point when it comes to that sort of thing. Thanks for the response!
I'd definitely like to write more on the concept since I truly believe it could be useful, at the very least as a source of hope. It's all too easy to feel depressed diving into the viewpoint of suffering-focused ethics, but that probably slows motivation that would be more effective otherwise. The possibility of forgetting suffering to soon is a good point to remember, I'll take a look at the essay linked. Thanks for the response!