Yes
No
This is actually a tough question. I love Jean, but i do think dead should mean dead. I guess I can't answer it fairly since I'm a little biased
The problem for me and probably a lot of people as well is not necessarily the fact that Jean is resurrected (although, as someone has already said here, the way you do it matters. A cocoon was a little lame but ok.)
but my problem with Jean's story being undermined is the Phoenix Force being written into every other character, and diluting the meaning/importance of it.
Rather see the phoenix buried than jean tbh.
(...And yeah, RE: Uncle ben, mar vell, gwen, etc. you know they were different character types before you even listed them so....yeah. Different purpose in the story.)
Phoenix Force being written into a MacGuffin any character can access took place during Jean's 2nd death anyway. The most that did was undermine the idea that the Phoenix is Jean's Super Saiyan instead rather than being another entity. But CC kinda screwed that idea himself when he was writing Rachel.
"Cable was right!"
Mar-vell was pretty important in his own right, being able to hold a solo for years, something most X-men characters can't do.
Likewise, having Scott marry Maddie was also a way of undermine his own story anyway- "yeah, Jean's dead, but here, Scott has someone that is an exact replacement, and is all so beautiful no one would think there's anything wrong with that".
I can't really label Scott x Maddie under the destruction of Scott's story since the most we know is that CC was planning to write out all the old guard out anyway which Maddie helped Scott to do until X-Factor meddling. Who knows what galaxy brain tactic CC was planning when he had Scott hook up with a woman that looked like his deceased lover.
"Cable was right!"
Claremont himself demote Jean's death by making Maddie and Rachel to replace her. That moment Jean's death became meaningless and served no purpose.
Considering her name and Scott's, seems pretty clear to me he saw Vertigo, but missed the point and thought it was a beautiful love story.
Claremont wanted Scott out because he wanted Storm as the leader, but didn't want to let him go the Avengers or, considering Beast, Angel and Iceman were on the Defenders, join them, and be out of his control and unable to be used when he felt like it. Ended up backfiring, of course.
Rachel was created for the DoFP storyline and only purpose was to have someone with Jean's abilities for the plot to work. She only takes over fully for Jean before UXM 200 and CC never portrays her as being similar to Jean outside of power set.
And as I said before no one knows what CC's real endgame with Maddie was.
"Cable was right!"