In the Action
It was only a matter of time before the first lightning soldier army got exterminated.
They were too weak for their advantage in numbers to gain the upper hand. Their 'tech' was rather interesting, but ultimately not equipped to pose a credible threat against a reasonable number of Dread Marines.
That did not mean the lighting soldiers were weak in an absolute sense.
A regular first-class infantry troop would have suffered a lot more casualties if it tried to defeat a larger force of lightning soldiers!
The only reason why the lighting soldier army got steamrolled was because the Dominion of Man was the best troop carrier of red humanity.
Not only was the dreadnought capable of deploying hundreds of thousands more Dread Marines, each and every single combatant had access to the best possible infantry gear!