I'm gonna go against the grain here and say I generally like super hero deaths in comics even though the execution in this particular instance is pretty awful.
Removing an iconic character from one of the big cape universes for a time, and replacing them with a new version of that character, almost always produces fertile ground in which new themes and concepts can be explored and allows a lot more license to experiment within that book. It can be exciting, the audience will tolerate more outside the boundaries of what they usually accept and if it's a promotion for a sidekick or what have you, it can bring a lot of enduring growth, change and history to that character, even if they end up reverting to their classic role.
I actually dislike comic deaths that are intended to feel permanent, because they're never *actually* permanent and I think it's bullshit for people who truly love those characters to have to put up with them being "dead" for ten or twenty years. Jean Grey I'm not your biggest fan but I'm talking about you.
I'd also challenge the notion that having the character drop through a portal or whatever for a couple years is significantly different or somehow less objectionable, like it's practically exactly the same. I don't think it matters at all how they cleared the board for some other character provided it's always temporary