You do understand that you are a minority? Right? The word "underrated" was a generalization. But that should be obvious as guides such as this are always intended for the less experienced.
Do you understand, that BSN community isn't exactly the place where "less experienced" players habitate?
Ok. Lets talk your guide, and why you shouldn't "teach" yet.
1. You constantly talk about one hitting and packing as much punch as you can, while using crusader. You either not very familiar with shieldgate concept, or don't have an access to damage calculators. Either is a sign that you have a lot to learn yourself.
Any kit with good passives (OG Turians, Destroyer) and any winfiltrator can kill (w crusader) any unshielded gold+ mook with one headshot and any shielded mook with two. If you use phasic ammo you can one-headshot-kill gold nemesis with some of those kits. Sexbot, due to the facts that her cloak (last rank) modifies base damage (so phasics will do more damage to the shields) and snapfreeze has a debuff with "damage from all sources taken" property (i.e. even more damage from phasics), can break through the shields of centurion. That is as far as you can go with onehitting w crusader.
2. Cryoblast is simply stoopid to skip. You probably don't understand the multiplicative nature of debuffs. You loose not 25% of base damage, you loose 25% of all damage (CB debuff applies even to ammo damage if memory serves).
Assuming crusader does 800 base damage per shot (it does slightly less) with HI you loose approximately 500 points of damage with each crusader shot (2000 from clip). And if you think doublehits (where crusader excells) you loose aproximately 4000 to 6000 thousand damage with each clip. It's a big deal for bosses.
For example - if you choose duration cloak but spec into CB fully, you will loose less boss damage (where it really matters) in comparison with damage cloak without cryo blast.
3. You talk about piercing mods in terms of armor damage, that's the sign that you barely understand the concept of armor damage reduction, which barely matters for crusader at all. Though you untintentionally modded your crusader in the best possible way, while armor piercing isn't such a big deal, penetration is. And while it's unwise to stack piercing mods on any other shotguns, crusader is a whole another story. I doubt you though (or knew) about double-hits on banshee. You rather demonstrated "armorphobia" so typical for poorly informed players.
While you did a good job recording and editing the vids, your guide is malignant for newer players, as it relies on your understanding of the game rather than on meta mechanics (the thing where newbies really need the guide).
Nothing personal.