@Phorm
I think it is probably a lateral move, but here's the pros and cons as I see them

Pros:
Senator Starscream is always gay, bisexual, and or trans. So he is unlikely to take any negative actions on that front.

Senator Starscream is from a working class background and has a hatred for generational wealth and inherited titles. So he might pass an estate tax.

Senator Starscream would be the most physically attractive person ever to lead a political party in the Senate.

Senator Starscream does not know what a Jesus is and does not like sharing power. So the christian right would likely not have their hooks in him.

Senator Starscream loves super science and would fund the hell out of research.

Senator Starscream is too large to fit in the Senate, this would lead to making an ADA overhaul of the building.

Neutral:
Both senators McConnell and Starscream take a brutal short term view of energy policy. Starscream wants to convert all of Earth's fossil energy to stable energon cubes so he can get wasted for a few million years, McConnell wants money.

Neither senator supports any welfare programs. McConnell because he's evil and Starscream because he is literally inhuman.

Negative:
Senator Starscream was second in command of one successful fascist coup already, and will absolutely do it again.

Senator Starscream is a mighty combat aircraft and a giant robot. His presence in the Senate would give them a standing army, which is not ok with the constitution.

Senator Starscream is a frustrated megaphile and will roll over and do what ever he's told if the speaker is bigger than him and hot.

Senator Starscream is functionally immortal and cares nothing for the short lives of meat.

Senator Starscream has they cyberforming of earth as a major plank of his platform, and this will inevitably leave earth uninhabitable by human life once the atmosphere is completely stripped away and the dirt replaced with metal.