Depends

If it's just low effort ports in HD, no way

If they are true remakes made from scratch with a new engine/Oddysey enginee, day 1

If they are remasters like Xenoblade Chronicles, with new textures, assets and some extra content I will wait for some reviews before buying

It depends on how much they updated the games. If 64 gets a full graphical overall I'll almost certainly get it or if Sunshine gets a full gameplay overall to iron out the problems I'll almost certainly get it. If if they're just upresed ports then I won't since I have all those games already. I want real improvements that make the experience fresh.

I heard a rumor that I get it.

Yes, I would purchase said collection if it were to come out.

Xenoblade is a remake tho

So, it doesn't reuse the Wii version engine? 

Yep, it uses the Xenoblade 2 engine. They remade it so it can be on par with X2 (engine-wise and chara design wise)

Definitely. I've been hoping the rumor is true.

I remember being so frustrated at Mario Sunshine, I would die 100 times on certain area where they took the water pack away...and that horrible Pachinko level. But I needed to 100% Mario games back in the day, where now a days I don't feel the need to 100% them. As much stress as Mario Sunshine gave me, it's the Mario game on the collection that I want to play the most since its the only mainline Mario game not available on multiple consoles. (well 3D World also but that just came out a few years ago.)

The only 3D Mario games I have not played are Sunshine and 3D World. If they are included I will bite. Not really interested in replaying 64 and the Galaxy games, even though they are amazing.