Enchanters are invaluable in my opinion. Crowd Control is very different from EQ1 in that you don't pull a group of 5 then mez all but 1. Usually an enchanter can only mez 1 to 2 adds (if I recall correctly), but enchanters do so much more to make a battle go smoothly. As far as I am concerned I will take an enchanter in my group any day of the week. Soloing may be a bit tough for an enchanter as thier damage output is low compared to a sorceror and summoner, but still very good nonetheless.
This changes at the higher levels. Enchanters (illusionists and coercers) sub for a second healer and make the group just flow. The best XP day I have had was a group in RV with one healer and a chanter. Mezzing whole groups then singles as well, the group never ever had so much as a power dip, much less downtime. We had to go to a dedicated puller, as opposed to tank-pulls, just to keep up. These were mobs that were 3-5 levels higher than the group average.
The probelm is the until the later levels both the enchanter and the other classes lack the damage dealing capacity to really make the "mez and kill" method work as well as two healers and AoE damage.
I was not a believer until I accidently pulled two groups 4 levels higher than the group in RV (we were 39-40, the mob groups were 43 and 44) with one healer and a coercer. I was expecting to die and told everyone to prepare to run. A few minutes later when I had failed to even drop out of the green, I enjoyed my words with farva bean and a nice chianti. Chanters are just as powerful as they were in EQL, its just they aren't required, and there are other viable methods of grouping.
EQ2 is very flexible about the way one can put groups together. Its really a good system.
They are adding tons of solo content. So much so that once you get a good group, it can be frustrating to have it get in the way.
Also, in the last patch they bumped solo and small group xp in a huge way. I mean, it was shocking how much xp I was getting per kill while harvesting. At this point I think the delta between group and solo xp is smaller than I have seen it in any game. Soloing is certainly a viable way to advance.
As a disclaimer, I play a plate class tank, a Bezerker. It seems that the tanks in EQ2 seem to be the best solo classes. That is just from my and my friends' anectdotal perspective. From what I read, every class can solo. I think that Paladins are probably the best, again from what I read in game, along with the other tanks, and healers. I would think that casters probably are the "worst" although I have a buddy who solos with his wizard fairly regularly. He dies a fair amount doing it; in his words, "either they die fast or I die fast".
My advice? Play what you want. A healer (warden or mystic for maxium would be the most versatile) would allow you to solo, with movement speed buffs, and have just an important role in any group. Plate tanks do this as well, although Paladins seem to be less favored for raid tank. Note less favored, not less viable. I have seen a Caldron Hollow raid fail because of Pally bias. They choose a lower level Guard over a higher level Pally and the raid failed on the last mob because the Guard just couldn't stand up to the onslaught.
Good luck and good hunting!