Love colored magic
Can you elaborate more? I'm not convinced. To me, ground typing is more of a disadvantage than advantage. I introduces a weakness to Water and removes your resist to Ice (relevant) and Grass (not as relevant). In return it gains an immunity to Electric, which is for the most part a very uncommon attacking move outside of Volt-Switch. Bolt Strike is rarely run in BH in the current meta, and when it is, it is usually run on protean sets which can easily take out Steelix with a different coverage move like V-Create. In that replay I didn't see any examples of what Steelix can do that Aggron can't. Right now the only thing it has is slightly greater special bulk. Aggron can run a similar regen set to check Mega-Ray, it just ends up having slightly less attack and physical bulk.Since it's still not anywhere, I'd like to nominate Mega Steelix for D Rank. I have been using the RegenVest set lately in a partnership with Mega Diancie to dispatch Imposters of it as well as most other -ates. It can't switch in on Kyu-B like other Steels can, but it has slightly more bulk than Mega Aggron. I've been using it to spread status via Nuzzle to allow POgre and PDon to set up or rip holes respectively. It has been functioning as an excellent pivot. With some attack investment, it can OHKO Mega Rayquaza with Icicle Crash, as well as Mega Diancie via Gear Grind. Sacred Fire is another option to spread burns.
Steelix-Mega @ Assault Vest
EVs: 252 HP / 212 Atk / 44 SpD
- Gear Grind
- Icicle Crash
The EVs are the ones I have been using, and they avoid the 2HKO from Aerilate Sharp Beak Boomburst, allowing you to switch in and OHKO with Icicle Crash. Gear Grind is for Mega Diancie, while also hitting Kyu-B (but you can't switch in on Kyu-B). U-Turn is obvious for momentum and my team appreciates Nuzzle to Paralyze faster Pokemon so MegaLix's teammates can wreck. Like I said earlier, Sacred Fire is usable over or in tandem with Nuzzle for more status spreading, burning Shedinja, and to hit opposing Steel types. The thing I like about Mega Steelix over Mega Aggron is its Ground typing. While this makes it more weak to POgre and Ice types, it gives it a nice Electric immunity allowing it to switch in on Bolt Strikesand Nuzzles before pivoting out. Here's a replay of a battle I just had where MegaLix spread status and annoyed the other team to allow PDon to finish up:
The Paras on Arceus and Deoxys in particular were helpful, while it also allowed Lugia to be weakened.
I understand that Mega Aggron or Registeel will outclass Mega Steelix in the majority of situations, but I feel like the Ground typing and ability to switch in and KO Mega Ray is a nice niche for Mega Steelix and enough to give it D Rank.