Seems to be, from reading this one and other forums about stunlock is that there are basically two groups of people. One that thinks that constantly having to reload the game is immersion breaking and is almost like cheating, and another group thinks that loading is fine and that's how you basically learn the game.
First group basically hates stunlock and the other one is fine with it.
I'm kind of in the middle of it, I like stunlock abilities however it is annoying when you get ambushed out of nowhere and you can't do much about it. I think the problem lies elsewhere currently. To me its ok if I start an encounter and one of my guys gets stunned, however its not cool when 2 or more are stunned right off the bat.
I think a way to resolve this is to bring back the formations from the last game. I think this will resolve the issue of your whole group being stun locked. I remember last game once that was introduced the game was still challenging but I had to reload a lot less due to feeling I got screwed by the game. If I lost it was usually my fault.
The first play through I did in DOS 2 I kept getting annoyed for my whole party getting hit what seemed like out of nowhere and reloading a previous safe and arranging my guys accordingly for that encounter kind of cheapens the experience of said encounter I think. Having to reload every time you get ambushed so you can set up properly makes it so that there aren't actually any ambushes in the game.