...Was pre crisis Martian Manhunter much weaker than the post crisis version? I got my copy of the Superman vs Mongul TP yesterday and issue 27 of Superman from 1980 has Martian Manhunter trying to stop Superman getting a crystal key and failing. Supes easily overcomes MM who doesn't use any telepathy, phasing etc and Superman is shown to be comfortably stronger. I am not an expert on MM, but do know that in Trial of Fire he overcame the whole JL whilst possessed. So was his pre crisis version much weaker compared with Superman than the more recent versions?

Pre-Crisis MMH did have telepathy and phasing, its just that the story wasn't well thought out and Superman was stronger and faster by a mile.
Although even recently in Morrison's JLA Superman managed to stalemate an angel that MMH was utterly beaten by.
I guess it depends on the writer but in recent years, since Kelly's JLA MMH is seriously more powerful.