It's already mega
Mega Arcanine..... Omggggg.... *drool*
As far as Tyrantrum goes,
'F$$k yeah! Bout time we get some kickass prehistoric pokes back in, tbh I haven't taken a liking to any of them since Aerodactly (which is in need of a kickass evo or mega evo)
As for its speed, I'm gonna quote Jurassic Park.
"We've clocked the T-Rex at 32 miles an hour"
Yea. A moving tank. F$$k yeah.
Oh yeah. Now listen to this song ^^ and stare at Tyrantrum. Imagine it just wrecking everything. Yep, according to this song which matches my excitement,
"It's a mutha f$$kin' T-REX!!!"
Aurorus' signature move, Freeze Dry, is gonna be super effective against Water-types... despite bein' an Ice-type attack.
The door to moves with their own typing rules has been opened! W00t!
This will be a notable buff to Ice types, assuming that a fair amount of them get it. I don't know if that will be the case or not, but we'll see.
Unless they actually confirmed that it's a signature move. Even then, stuff might learn it via breeding or something.