CURRENT TTK sept28 MY OPINION:
Tried the PVP mode today for the first time, and even with stuttering, the TTK was completely fine in my opinion. The maps are also larger than in the previous installment, so if you need another shot to get the job done in this game, raising the TTK, its still a low TTK at its current state compared to for example CSGO.
The reason I mention larger maps as a factor is that it creates a lot more hiding spots to get killed by campers, so checking every possible spot before moving is harder - And a more forgiving TTK should therefore be welcomed to prevent too many lockdowns - Again, the TTK is still very low, and it works both ways, so I can not see any problem with it. I got 7-8 kills in a few game rounds using the GEA3 battle riffle on insurgent side and the good old M4A1 on security side, they both got the job done just fine, being able to clear multiple hostiles without reloading.
I suppose secondary weapons/pistols are less effective this time around, and aiming for headshots will be more important than in the previous game when using pistols - But that should be fine as a pistol always was meant as an emergency solution, or a supplement to save ammo when taking out unaware enemies when approaching from their blindspot (in my humble opinion).
I have approx 14 000 PVP kills in Insurgency 2014, and experience absolutely no problem with Insurgency Sandstorm TTK.
If you have a problem with the TTK, I suggest having a look at your weapon stats if you have not already and choosing a weapon with higher damage, as the opposing team/enemies in this game have little to zero time to suvive when you spot and shot before they do (if you hit your target that is) - This is on top of having stuttering (I only have 8GB RAM, MSI GE70), so the TTK should be even lower when my rig is upgraded at some point, thus removing lag from the equation.
I have not tried out the bolt-action sniper rifles (M24 security side and Mosin-Nagant insurgent side) and suppose they should be one shot kills, even center mass with heavy armor on target, to remain relevant as viable options.
Yes the M24 use the same caliber 7.62x51mm as the MK14 EBR, and no, they do not need to have the same damage output because the MK14-EBR have a much higer rate of fire - And like every other game the weapons should be optimized to create fluid game balance above realism. Immersion is subjective anyway, and I never understood how anyone can describe a computer game as feeling realistic, though I suppose most people mix the word with immersion=)