Let's discuss your changes point by point.
If 1 would be implemented then players that are good at dueling would lose one great asset and that is real time updating on their target resolve status. Also, since inactive resolve ticks down at 25 point per second, getting hard stunned for 4 second will give you 32 seconds when any subsequent CC will put you in resolved (active) state, even a knock back would do that. Good player will profit from that by holding on their stun breaker to break the second stun /mezz . Nothing wrong with that but with the current TTK to give such long period of "immunity" to a player could upset the balance.
2 sounds good I see no issues with that.
3 is too big of a change for me to pretend I know how it would affect the game-play. If you are focused by several enemies with roots then you shouldn't be upset, your team can move. If you are rooted again and again by a single enemy then maybe we should speak about that class/spec alone (don't think we should though)
If 4 would be implemented you should welcome back immortal in 1v1 healers (the good ones will be able to keep up with 1vs2 comfortably.) Opening with a stun does not guarantees victory by any degree in fact (except certain classes) it just diminishes your winning chances since you lose a great way to interrupt a big attack of your opponent.
Stunned to death happens but it's more about the short TTK and glaring imbalances between the opposing teams then about the amount of CC. I rarely get stunned to death when I'm playing with people that know how to guard/taunt/peel/heal while playing in a team that gets decimated gets me more epileptic deaths than I can bear
Thank you for the constructive post though. o7