As far as this goes, Survival has very limited utility in PvE because thralls normally just stand in front of each other and beat on one another until one dies - so debuff time reduction is meaningless since every debuff timer will be renewed before it can expire. For a dagger-armed/cat/hyena follower whose attack cycle includes temporarily disengaging, debuff time reduction is marginally useful because there may be a rare instance when a stack falls off, but for the most part even then the debuff will have its timer reset before expiring even if the thrall has a huge survival stat. The only place where the current survival effect is useful right now is horses because the player can maneuver them into and out of combat enough that effects might not be renewed. It would be better if Survival mitigated the effect of debuffs rather than their duration, but that’d require serious reworking I imagine.
(I’d add that the way Agility works is fine, but disappointing; in principle, it seems like higher agility would make light or medium armor viable alternatives for thralls, but in practice it improves you less than you’d get by wearing heavy armor so you’re still better off with that. Perhaps there it would be better to make Agility offer more bonus armor when the wearer has less artificial armor (on top of the diminishing returns currently used), but that’d be a really complex rework that would need major balancing.)
That’s not directly apropos to the current discussion, especially since anything involving these two stats would take more coding to address their problems, but it does point to the general trend that the current topis IS addressing: the reason it feels like followers have “wasted” stats is that each stat has such a narrow range of impact. If there were more effects from each stat, there would be less of a tendency to view thralls as all-or-nothing based on one or two stats, and tradeoffs can become good things. If e.g. Str and Acc gave some AP, and Agi gave 1/5 or 1/10th the damage boost of Str & Acc to both, and Surv gave 1/5 or 1/10th the HP boost of Vitality, you’d get something for any stat gain, and as long as you didn’t have perks directly cancel out even “tradeoff” perks would sting a lot less than they do now. [Note that I propose no secondary effect to Vitality, because frankly it’s valuable to every follower no matter what.]
Basically, adding complexity allows for tradeoffs and makes it harder to have clear, unambiguous min/maxing of the same tiny handful of followers using the same tiny handful of gear with all the rest being useless, which is incredibly dull.