Being fast paced just makes more sense for a mech game imo. Have you seen how fast mecha anime gets?
And there's plenty of examples of the opposite as well. Gundam alone pretty much covers the whole range from grounded and gritty stuff with 08th ms team and IBO, to middle of the road stuff with the later OYW shows as tech advances to the utterly ridiculous stuff with Gundam 00 and Gundam Wing