Should they kill Ryder in DLC?

Both approaches have their pros and cons. As for myself I usually get attached to my characters but not to the point that I need them in any subsequent installation. Like I have already stated elsewhere, what really matters is that they give a satisfying conclusion to their story which does not mean that I have to see them aging or dying. As long as they have exausted their role in the "grande scheme" of things I have no problems in letting them go.

In DA both the Warden and Hawke imho had exausted their role as MCs. With the Inquisitor they got themselves in a more troubled position, especially after Trespasser, because his loose ends are somehow more "personal" than Warden and Hawke's. I don't think that The Blight and the Mage/Templar Wars are something that fall under their responsability, nor we should expect them to put an end to those problems.  The matter of Solas is slighty different because he is a single individual with all the implications that this could entail.

As for Ryder I consider his position to be even more troubled. I don't expect him/her to lead the humanity vs the Ketts, it could be him as well as someone else. But as "The Pathfinder" I expect him to retrieve the remaining arc(s) and to finish his father's business, because otherwise I would feel like he had not fullfilled his role in the story.

TL; DR As long as they finished Ryders's story they can do as they please. 

If they kill my Ryder I'm going to start a massive campaign to get him revived... maybe his adopted daughter should take him to an island and revive him and then disappear chasing some evil guys on horseback and he should wake up with the big scar on his face and gray hair... and the Nomad should definitely turn into a horse... and Ryder should learn to handle a swoard and everyone should just forget how to make guns... and people should be able to just conjure up fast travel gates (let's call them portals)... and we can all learn to love TW3 all over again.
    

It must be really disappointing to believe the world revolves around you and that all fiction should cater to what you want, because it'll never happen. Ever. Ever.

This way if and when they make an Andromeda 2 we can get an interesting and likable main character.

Also just in case you missed it this whole topic should be taken tongue in cheek.

Naw, you don't need to kill them to have a different protagonist. Look at DAI. Your old MC can even show up because they are not dead. Seems like a waste.

I actually think Ryder is very likeable. Both versions are well-acted. I think people's issues with Ryder is their lighter tone and lack of true Renegade options. This can be altered for MEA2, as by then Ryder might be a bit "hardened" if they return as the protagonist.

I'd prefer to keep Ryder as the MC, but if they choose to go with someone else and you can pick their species, that'd be awesome.