And now the blanks shall be filled, which shouldn't have had to be done in the first place...

 

Because Optimus is a Prime, I think.

 

Probably 'cause he just annexed a planet.

 

Or that.

 

He liked the way Optimus decapitated Galvatron (by destroying his body) when Galvatron was having a moment of redemption and begging for his life.

 

Begging for your life isn't much of a moment of redemption...

 

Optimus also has a Titan....

 

When Optimus told him why he was so evil, Galvatron seemed to have an epiphany.

 

Optimus and Sentinel have more or less the same attitudes towards governance, it's just that Sentinel is the sort of degenerate that Optimus intends to purge in order to make the galaxy great again.

 

Sentinel: You have a Titian, I have a undead Titan army and we're both Prime's so lets be friends.

 

He asked Prime if he was any different from himself, and then begged for his life when he realized Prime was actually going to kill him. He had no epiphany (which was the whole point).

 

I took it differently. But that may just be my pacifist bias.

 

I don't think Galvatron experienced an epiphany beyond "oh crap, I wasn't expecting Optimus to kill me today".

 

Galvatron was unrepentant 'til the end. Had Optimus accepted his "surrender" he would've betrayed Optimus and Soundwave the first chance he could and gone right back to being a Massive Bastard, which is exactly why Optimus put him down for good.

 

Maybe he thought, "Without a head, this body will be totally receptive to a headmaster, giving me synergy with the toyline!"

 

His body disintegrated as Optimus took his head off, so I don't think it's receptive to much of anything!