The Concierge said :It does put stress on the internal logic of the whole Force ghost idea...but I think dramatically, at least, it makes much more sense to show Padme to the audience again over Mace. Perhaps to reinforce the logic behind her appearance emphasis could be added to key points earlier in the saga (I could only imagine this in AOTC or ROTS) showing Anakin's 'mystical' bond with Padme through the Force...
I just posted in jest about the midichlorian thang over on the radical redux thread.
Maybe the Jedi had a slightly more sinister reason for not wanting their number to get too attached to other people, with a shared blood supply perhaps Padme had temporary Jedi powers during her pregnancy which could explain her death due to her strong connection to Anakin through love and her coming back to him as a ghost/memory, she could even be the explaination for him coming back as a ghost, Qui-Gon does say love is the key and Palpatine claims his former master could save the people he loved too (something I can't imagine Palpatine being able to do).
I suppose I should be more careful with my humour?
+++Strike that mothers and babies don't share their blood supplies, thanks Lord V for reminding me about basic human biology, always confusing for out of towners like myself, one heart...quaint+++