Quote from JutsuRaptor, my current team composition is going to look like: Metagross, Heliolisk, Vaporeon and Umbreon.
I'm thinking of adding in Crobat and Altaria, any thoughts?
Crobat to replace my potential choice band archeops and altaria to replace my potential ampharos, for typing.
I'm not really one to ask for advice, but I'll see what I can do.
I never liked Archeops to begin with because he gets walled pretty bad, in the sense that while he has great attacks and speed, a wall + entry hazards + status infliction hurt Archeops a lot, and defeatist kind of makes Archeops pretty useless so you have a dead weight pokemon in your party. Metagross in your party is a much better physical offender, so the need for Archeops isn't necessary. Since Metagross already has some of Archeops' moves like Earthquake, I think Crobat is a good replacement since he could be used as a flying type attacker to make up for Archeops, and he is much faster.
I don't know how much I agree with an Altaria change (unless your speaking megas), and this one really depends on personal preference since they fill different niches. I'm assuming Ampharos would be your special attacker, but Altaria isn't much of an attacker until she gets a few boosts with Dragon Dance. I like Altaria more because it has good typing, Vaporeon and Heliolisk to an extent already fill out the special attackers, and Umbreon + Metagross fill defense. Altaria makes for another physical attacker (and technically special if you want) that has moves that attack those Metagross can't compensate for, and since you already have Heliolisk, an Ampharos isn't really all that necessary (plus he's slow). Just my quick two cents.