Like the only use of the cap stone is letting plasma hit easier breakpoints with the spotting one. The melee one is self explanatory. The weakspot one I could make an argument for if they remembered to put a toughness node on that side. You will die, and not have enough points leftover to grab one from the middle or right.
They really should have made that mandatory toughness node connecting to grenades give 35 toughness if all the other 15s were going to be removed. Like most things it just seems like the over reaching goal of the project is to keep veteran down. At least Out for Blood will keep you decently alive on its own now…and seems to be fixed with melee. With a gimmicky loadout incorporating both 25 toughness nodes and 2 curios I had 249 overall, so returns of 20 toughness per kill. With the melee buffs.