I've found the auto-bio option from the extension really helpful in cleaning up profiles with GEDCOM junk. It will produce a basic structure and gives you a good sense of what's worth keeping and what's not.
I would save the list of children, especially if they not have their own profiles and are not linked.
I do try to clean up how sources are written a little bit. My own didn't import all that well, but I don't completely re-do them. My sources are already written close to EE style, so I cut the weird S### source number, etc. But I don't go find a URL if they're old sources and I didn't have one when I first created it.
I don't ever cut sources that were added by other people. They're there for a reason, even if they don't make sense to you. Though I will cut something that's not really a source like "Ancestry trees" with no link or way of identifying what that is or what came from it.
I cut things that relate only to the original database, but aren't relevant or provide information to other people. Like reference numbers or quality of information numbers.