Rift has provided us a way to multi-class essentially, I think it'd be very important if they clearly distinguish each soul by type.

I mentioned this in another thread somewhere, but if they made the types: dps, support, tank, healer, CC and made it so that there was no ideal group, that 5 support could shut down mobs/buff up hard enough so that a tank/healer wouldn't be needed, that 5 dps could bring down mobs fast enough no tto need a healer/tank, or that 5 CCs could continually pull groups and mezz all but one and burn them down 1 at a time.

Now, you'll say "oh but the 5 dps are going to bring down the mobs so fast that they could just blow thru content", well my answer is that make it so that any combination of classes takes x time + y downtime = z where z is always the same. So some mixes would kill faster but take longer downtime, some combinations would take longer but wouldn't have downtime.

I know, hard to balance, but if you seperate souls by types, then you can test it and each soul could have a specific role which would be clearly identified. This would support not having the trinity system since anything works. yet people could still find groups since everything and anything is welcome.