Sovereign screwed up so bad.

Not only did he fail in opening the citadel mass relay.

In doing so he causes a massive rearming campaign by the citadel races who thought they would have to fight the geth.

Also because he died and left his body floating around the citadel races could study it and come up with the thanix cannon. The thanix technology was used to kill multiple reapers in masseffect three.

It probably would of been better if he just waiting for his kind to make the journey from dark space.