I would say that to reboot the power Rangers you need to have a reboot with continuity. Make it sort of a reboot with new and older themes at the same time. (Think alternative earth). They could have Tommy come back as the wise older one to help guide them since there all so young. Maybe even give him the Green power coin to use in an Extremely emergency situation only. Like the last show of the season, something like that as he comes in with the Ultra powerful Dragon Zord to help the team win the final battle. Maybe meeting some of the others also as wise mentors, just maybe.