I've been wondering a lot about this lately but doesn't it seem so that the later representations of Optimus Prime depicts him as a physically weaker person each time all while Megatron gets stronger and Galvatron insanely strong ?. Think about it ! either Prime needs minicons or combinerbots or cyberplanet key or some combined mode just to get a slight edge over Megatron. I especially think about Prime in Beast Machines, Armada, Energon, Cybertron... I haven't watched much Beast Wars or R.i.D so I can't comment on that. Actually I only see Prime in G.1 as being a the worthy "opponent" to Megatron/Galvatron and actually being slightly stronger. Well that's just how I see it... what do you think ? Megatron may got stronger but his might got weak whereas it's vice versa for Prime ?