1) little behind but not so far to prevent us from getting brought to raids. the numbers are still being worked so I expect the gap to be closed come cataclysm launch. With all of the changes to mana regen going through, it is hard to say.
2) pretty even from my experience. We have more tools than ever for raid healing, and our tank healing capacity has been buffed pretty significantly IMO.
3) I'm probably going fill a tank healing roll in my guild, but i like tank healing. Restos will probably start off as raid healers because that is the roll we have filled for a long time, so raid leaders will probably keep them in that roll.
4) http://wowtal.com/#k=RfATLqOL.a8t.druid. with 2 points left over. If mana becomes more of an issue i'll drop points out of GoTM and move them to moonglow. or if i have a surplus of it i'll start moving points into genesis.
5) none other than to come into the expansion with that mindset that you are going to be learning a completely new way of healing. very little of the past 2 years worth of healing experience is applicable to cataclysm healing. If you keep an open mind then the transition will be a lot easier on you. Also, you have to weigh every decision: healing amount vs mana cost vs time. If the person needs a heal now then burn the mana. If he is taking consistent damage or isn't in danger of getting killed then heal them slowly. no more having to have people at 100% healing at all times for fear of an instagib.