Yes, No priest class can rez themselves in group or solo instances.
However, They have no need to really do so in solo Instances, you have to run back to your soul shard anyhow, and just clicking it grants you almost the same exp return as a rez, infact it may be the same. Downside to rez during groups is that, those rez'd will have only a little hp and power, making for downtime. Now priests that solo can just die, run back, click body and go on thier way.
Also, To top off the points about how each healer differ's compared to the rest in EQ2 and compared to the counterpart in EQ1.
EQ2
Clerics: Strong Heals and heal over time spells. Also have good armor and modest tanking ability. Clerics of EQ1 were saught after cause of thier single best healing and buffing abilities, now its still nice to have a cleric but your not forced to need one. Other not is combining riest classes in groups makes for huge difference in the groups abilities. 1 cleric in group and its a good group, cleric + either shaman or druid and its awesome.
Shaman: Strong ward abilities, and tied with druid on earliest group heal at lvl 14. Shaman retain thier chain armors and spears, but they also gained a substancial increase to healing rates over EQ1 shaman. This bridges the gap between the shaman, clerics and druids making thier Wards very useful group wise and sometimes the tide of battle can be tiped with just a single well timed ward. Shaman also still retain thier animal form of bears but they also have illusion forms for other animals.
Druids: Yep the tree huggers came back with EQ2, and man they was blessed. Druid classes have the only true HP regen ability in the game thus far, and it rocks. Specially when mixed with either the clerics HoT or the shaman's wards. You'll also find druids still have some massive dots. Infact I've talked with some that use nothing but dots on things while they tank it using thier regen to heal themselves. This compared to the old EQ1 druids, hasn't changed much minus ports. But then again, the worlds in disaray and the frigin druid circles are torn to hell and back, so where would you wanna port to?
In closing, All the priest classes gained and lost things its true. Druids lost ports, clerics lost self rezes, and shaman lost thier pets, but they all gained something far better. Solo abilities, which sets them a couple notches above some of the other classes in EQ2. All in all I think priests that solo have the lowest down time of almost all soloing classes. All do it well and can protect themselves well while doing it too, with clerics falling to 3rd in soloing cause simply they lack SoW for a minor speed boost between mobs, which really isn't a disadvantage. Just don't roll up a priest and expect them to be all powerful healers strait out, cause its only when you combine types of priests into groups that the real potential comes out and shines.