Diablo III: Reaper of Souls

A lot of skills lack proper scaling.

I completely agree, and it's not even just the healing skills that need better scaling. A lot of the damage skills have pathetic damage output, especially with their runes. A lot of runes add terrible 20% Weapon Damage extras, while other classes will get Runes that add massive effects ALONG with 50+% additional to whatever it did before, if not way more. Most of the skills have runes that seem to do just about nothing. A good example is Fist of the Heavens. All of the lightning runes, except the one I describe below, and the Holy one....what do they do that's different from the original skill? They don't seem to do anything that was worth having a rune for.

I don't believe the Crusader has any dedicated 1v1 spenders either, except a different Shield Bash rune.

The only Crusader skill that's a decent 1v1 spender (I assume by spender you mean Wrath usage with no CD) is Fist of the Heavens with the rune that makes an electric storm appear where you attack, and multiple spark between each other. If you shoot multiple in the same location, and the mob doesn't move, or you put multiple in a decent catch-all grid (for a moving mob), it does some really nice damage. But it's really easily, and frequently inadvertently, countered. Sometimes mobs just run around for no reason, and if you use Shield Glare with the Charming Rune they just circle around you making it overall wasted if you use Glare after you use Fist, and sometimes after too.

The only other 1v1 I can think of is Heaven's Fury with the last rune. It turns it into a no-CD light beam from you for 40 Wrath. It does decent damage, but it costs so much Wrath that it doesn't output enough damage for the cost in my opinion.

Phalanx is terrible so far.

Phalanx Bodyguards is basically the only decent one, but it comes with a cooldown that's rather long for the effect. It's a decent meat-shield when it works, but often the mobs just ignore them until it's way too late.

Blessed Hammers lack a bit of power since they're so cheap, but they really shred low difficulty well.

Blessed Hammers is a very nice skill before about 55. Once you start getting close to 70 they lose all functionality. I'm not sure why, I found myself using them less and less and the times I did use them I did nothing notable with them. I remember the first Cursed Chest I ran into I soloed exclusively with Blessed Hammers, then one at 67 I didn't kill a single mob after using all my Wrath with them. I might be exaggerating a little, but it certainly felt like I wasted all of my Wrath for no reason.

I don't know what they were thinking with Justice either. That skill is just plain terrible. There were several others that I couldn't understand the point of them, either, either because a rune on another ability did the same exact thing, or just because the effect seemed pretty pointless to use an entire skill slot on, I don't remember. A lot of the Laws need effects that work outside of Empowering them, too, because they're way too mediocre for a 5-second effect / 45-second cooldown.

Overall I agree with your general synopsis of the class. I heard it was really overpowered in Beta, so I suspect they may have done a Nexon and overly nerfed it into the ground instead of balancing it properly.