just my idea of what g1megatron might look like with a classics style figure modeled after animated megatrons battle coptor form

energon bulkhead for the body minus the weapons weapons pod pack head arms and shoulders and hands

cybertron vector primes head for megatrons head

cybertron defense for e scattershot for the new arms shoulders and hands and arm mounted multimissile pods with store away cyberkey activated dual blaster and fusion cannon still left intact in the missile pods

ditch the main rotary weapon thing from energon bulkheads back

give him that spiked vcutting disck scissor claw dragon wings backpack wespon form beast wars 2 galvatron in place of the main rotary assembly but with it and the energon bulkhead/megatron figure being modded in such a way that it can still detach from the figures back to be used as a hand cutting claw weapon in robot mode and serve as the main set of razor sharp scissor cutting wings for the hybrid jetcoptor vehicle mode

give him cybertron wingsabers 2 parts store away swords and a g1 style colorscheme and bam you got yourself one very incredibly well armored megatron that is sprorting enough firepower to take on a whole battlaion of autobots +optimus prime all at once

hell with the proper colorscheme this megatron kitbash figure could jsut as easily serve as a classics style beast machiens obsidian or even a suitable body for a pre beast wars megatron as well