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Fire/ground is not that bad of a typing. It's neutral to rocks so it doesn't lose 25% hp switching into rocks. It's immune to electric type moves and can't be paralyzed by them, and gets STAB ground moves which 90% of fire types get.
Its only weaknesses are water and ground. Yeah its 4x water, but was litten really going to tank a 2x hydro pump in the first place? I say the less overall weaknesses, the better.
plus look at Primal Groudon.