I think if Mace would have let Anakin go, he would have felt better about the council for the fact that they trusted him enough to let him come. So along with his fellow Jedi he would arrest Palpatine and without Palpatine's influence he would have resolved his issues and wouldn't turn to the darkside.

i'm not sure either the same thing would happen or palpaine would have been arrested but not killed

I agree. Also a bit of the first option with Anakin stopping Mace from killing Palpatine just in time. (Is it weird that I can sort of see it happening?)

omg same but if anaakin never made it in time to save pelpatin in the film he would of been a jedi still

Hmm... I think maybe Mace would have told him to leave after Anakin got angry... then... uh... Anakin probably wouldn't listen and kill either him or palpatine.

He thinks Palpatine is one of his best friend so I'm sure he can't see Palpatine dying in Windu's hand.