In addition to Adaptability Dragalge being a thing, Rock Head Tyrantrum will become a thing in the future. Why? Because of the Generation Showdown tournament handing out a Rock Head (or was it Sturdy?) Tyrunt as an entry prize. I'm pretty sure that Tyrantrum has Rock Head as its DW/Hidden Ability.
Anyway, Tyrantrum is alright in RU, but hasn't made much impact in OU because of its relatively common weaknesses. With Rock Head released, it can now use a recoil-free Head Smash as its Rock STAB instead of Stone Edge.
Potential sets:
-Dragon Dance/Rock Polish
-Head Smash
-Outrage
-Earthquake/Fire Fang
Nature: Jolly/Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Lum Berry
Ability: Rock Head
or
-Head Smash
-Outrage
-Earthquake
-Fire Fang
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band
Ability: Rock Head
This is definitely welcome news, as it would make Tyrantrum now have a harder-hitting STAB with no drawbacks (other than the subpar accuracy). I would imagine those who receive one may breed them and then release them onto GTS and Wonder Trade.
Also, love the movesets you suggested. I could imagine it becoming a powerful threat.