Guess I'll answer since I already asked about on Smogon. I'll start off with the question on why Mega Aerodactyl is RUBL and not in NatDex OU and UU. Here is the response I got for why Mega Aerodactyl isn't in OU or have some sort of niche there:
Rocks weakness, unreliability in breaking, no real defensive niche besides checking heatran, horrible typing, and as such can’t set up if you ever wanted to use dd/hclaws
Source
As for why Mega Aerodactyl isn't in NatDex UU, it's because it's not used enough on the NDUU ladder (and NDUU ladder doesn't always reflect the meta, so....). It's B+ on the NDUU Viability Rankings as of now, but that may change since Iron Boulder exists, which makes priority moves more common. If you want to use Mega Aerodactyl, use it in NatDex UU where it has viability.
As for whether you should use Hone Claws or Dragon Dance, Dragon Dance is better since Mega Aerodactyl wants to have a speed boost(s) to outspeed faster Pokemon. I get the idea of Hone Claws to boost accuracy since boosting and having a chance to miss can be frustrating, but Dragon Dance is much better. Iron Tail also doesn't really provide much coverage that Mega Aerodactyl's other moves don't already hit. Here's the Dragon Dance set uses in NDUU:
Aerodactyl-Mega @ Aerodactylite
Ability: Tough Claws
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Dragon Dance
- Dual Wingbeat / Roost
- Stone Edge
- Earthquake
Earthquake provides good coverage alongside Stone Edge to hit Steel-types not named Celesteela. Roost can be used instead of Dual Wingbeat for HP recovery.
TL;DR Mega Aerodactyl should use Dragon Dance since it wants to have the speed boosts to outspeed faster Pokemon. Mega Aerodactyl is in RUBL since its typing doesn't help it in NatDex OU, and it doesn't get enough usage in NDUU, with its usage may being lowered due to Iron Boulder being in the tier.
Hope this helps!
