On crit buffs, yes considering crit buffs are limited in time, so this pretty much skews the maths more towards nerf since you don't actually have infinite samples to work with, and tons more variability.
Spreading consistently is a thing that applies to stinger, and even then, stinger's not exactly the first weapon skill that comes to your mind when you think a good grid.
With a 20% boost to damage and a ~10% chance of occurring (at slvl 20) that's approximately a 2% boost to overall damage (now that it can occur on every attack) and can be considered fairly reliable. From what someone mentioned earlier it occurs in a different frame than assault damage which means that the 2% is similar in power to a 3% increase in assault.
That makes the Spear similar to an Assault (L) weapon from the current assault (M). Not terribly bad for an SSR I think.
Dejnov.
The thing with probability is...
It's that. Probability. The numbers you see as an average is represents not what will actually happen, but what may happen. The probability will probably only truly reflect the actual thing given an infinite amount of samples, but there's no such thing as an infinite number of turns in this game. What you're left with is a setup that sometimes works super well in your favour, and sometimes not, and sometimes completely cucks you. In that case, I'd rather have weapon effects such as vigor that also happen to fall on a different frame for calculation that doesn't fall solely on invisible RNG.
That said, assault still king, so this kind of debate is really peripheral.
Question: I have gotten all copies of Rahab (and her knife, and some other goodies). I still dont have a full SSR Eidolon grid, and I'm a Light main (not sure if this part is relevant. In fact, is it?). In this case, is it better to sell her or train her up?