1). Solo play...not much has really changed.
2). We can't make up for poor play from other roles as much. DPS needs to pay attention, tanks need to interrupt and we have to pay more attention to what we're casting when. As for specifics it really depends on the fight mechanics.
3). TBH I have not tried post 1.2 I just don't see being as effective as we were before and with being automarked, dying over and over and over just isn't fun to me.