I like the Chakra ability. Having it active makes a Holy priest feel a bit more awesome and gives him access to cool new Holy Word abilities. Holy priests will need to use Chakra since we are balanced around it (in this way, if true, Chakra doesn't actually make a priest awesome ... rather, it makes him adequate). So, I have concluded that Chakra is as essential to Holy priests in Cataclysm as Maul was to bears in LK.
The issue I have (and about which I have no corrective suggestions) is that Chakra can be virtualized the same way that Maul was.
A Holy priest will necessarily want to keep the up-time of Chakra maximized, since it will be necessary to be competitive. Therefore, a Holy priest can macro Chakra with the abilities Heal, PoM, and PoH. This completely makes Chakra a passive rotation and not a decision.
When Chakra is available and a Holy priest casts Heal, he automatically gets Serenity and keeps it available while doing single-target/tank healing for as long as he is in that role.
When Chakra is available and a Holy priest casts PoM, he automatically gets Sanctuary and keeps it up any time he casts PoM/PoH in a raid healing role.
One question is whether roles in Cataclysm are as binary as they were during TBC, i.e. a healer on tank heals stays on tank heals for the whole fight. Maybe in Cataclysm healers will switch between tank and raid heals more often which would bring back a decision process for Chakra. However, if the roles are as binary as they were in TBC, then Chakra can be treated exactly like Maul was. It is an essential ability that can be taken completely off the action bar.