I can't help but feel that this question being asked every few years is a bit disrespectful to MM. I know I'm reaching here, but I think a lot of people only see one side of this reunion (MP joining) & not the other (MM leaving), & I think that implies that his presence is just an absence of something else, rather than an actual contribution to the band. It's fine if you don't like him, but just say that instead of ignoring him.
I don't think this is true at all. I know I have my preference - I've stated it - and there is not a SHRED of disrespect for Mike Mangini in any of it. And if asked I would state my position to him face-to-face. It's part of the gig. You don't replace a founding member like that without some acknowledgement that the discussion is going to be had. The list of people in that position - Dio (twice), Nielson, Morse, Bayley, Hagar, Thayer, Singer, Davison, Howe, Hogarth, Powell, Belew, Wilson - is as long as my arm, and it's INEVITABLE that the question would arise. I think it's denying reality to expect otherwise (not saying you are doing that). Now, HOW you answer may be a different matter, but just asking the question is not in and of itself disrespectful.
I think it's a mistake, generally, to view these things in such a binary light. I LOVE Sammy Hagar. I have (almost) all his solo stuff, and greatly look forward to his new work with The Circle. Love the guy, love the musician. Saw him in a little club with Chickenfoot and it was amazing. Having said that, when I think Van Halen, I think "Dave Roth". That doesn't minimize my feelings for Hagar even one iota. We're ALLOWED to have two different, sometimes competing, feelings.