You aren't using them right. Stop charging blindly into danger. Rather, scout with a cheap unit first, identify easy kills, and swoop in like a hawk. Or else ambush. Wait behind a sight-blocker, and startle your enemy with a face full of assault rifle. Or else wait until the storm hits. But don't ever spearhead an assault with your most expensive/valuable unit. They suck royally at range. Who needs armour when you have a meatshield?
This.
I use Shocks extensively, I think about 80% of my games I utilize Shock doctrines nowadays. The high reinforce cost is justified by the shear amount of damage they can do against all infantry/support weapons if they find the right spot to enter the engagement safetly and at close range. The reinforce cost is easy to avoid as you can utilize healing station. Don't play wildly with Shocks and keep them present on the field til they are down to 2-3 men, send them back to heal at every given opportunity when they are low health with 4-6 men.
Play smart and don't overextend them, because as you say the reinforce cost is to damn high. It is part of the reason why in 1v1 games I will only ever field 1 Shock squad and the rest of my infantry is Conscripts (3-4 squads).
The 480MP base cost. This I have an issue with as at it deters early game Shock play without severe risk. I often take this risk, however within good measure otherwise sometimes you must go Guards.