-3 (real 24 hours) days time limit to rescue captured Kaz.

wtf??????

An overall timer? Nobody likes an overall timer.

I have a fetish with horses pooping, so this game will be GOTG material to me.

why do so many people love Majora's Mask then?

Because you can go back in time, effectively removing the timer's penalty!

this is true.  Well I'm sure it's a generous time table and you can most likely do everything free-roam and side-missiony afterwards.  Adds some tension 
I suppose

I doubt saving Kaz means the game ends, so yeah. The time restrain on Phantom Pain will mostly serve to make you focus on one thing while learning the basics of the game.

Considering his importance in Peace Walker, I'm guessing you unlock a big part of the game once you save him.

My Atelier & Pikmin 1 days prepared me for this!

(Seriously, though, I have absolutely no problem with time limits in games.

personally this isn't a problem for me anyway.  I normally focus on the main story in open world games anyway then do all the side stuff then all the collectibles if i'm still interested

Neither do I have a problem with it. Dead Rising is one of my favourite games ever and that game has a timer constraint looming all over you.