I am more then open to putting rulers in there, I just don't think i have enough dragons to make them useful, but if you could could post your opinion on what i should do with it that would be a great help
What should i put in to replace plaguespreader and what about the side and extra decks?
I would replace 1 plaguespreader for Honest.
Also, I wouldn't add any dragon rulers to the main deck, they don't add much synergy because they can only use banish other dragons and you have no other level 7's, other than Dark Armed Dragon, in your deck to xyz with.
For the Side Deck:
I would -1 Decree in the side. Its a personal preference but you have lylas, rykos, mst's so it might be dead.
I would also maybe side maxx c's (2 or 3) for match ups like infernity, karakuri, mermail, etc.
I like the D.D. Crows, they're very good (maybe drop 1)
For the Extra Deck:
You should at a Gaia Charger.
You don't really need a Star Eater, I would replace it with generic rank 4 such as maestroke or something.