The only thing I can really say is that groups who have an opening and
don't want a bard just don't know what they're doing. I'll be the first
to admit that a bard isn't as good at soloing as many other classes, but
there are few if any classes who can add as much to a group as a bard
can.

Yes, if you look at a group in terms of one battle only many if not ALL
classes will contribute more than a bard. Will a group do more damage
in a battle if the last person added to the group is a bard, or a
warrior? Or a wizard? Will the group heal faster if the last person is
a druid or a bard? Or a cleric or a bard?

But looking at things these ways are shortsighted. Bards cut a groups
downtime by a HUGE factor, and less downtime means more kills per hour,
and that's what matters to powergamers. Bards also cut travel time.
Bards let a group bust camps. I know, I know, I'm preaching to the
choir here, but these are the sorts of things you should tell those
*ahem* stupid group leaders out there who don't want a bard.

Tell them that having you in the party compared to another wizard or
another tank will mean they'll get 20% more experience at the end of the
night. Now if their wizards blow all their mana every fight, having a
bard there isn't going to speed things up unless you're level 32, but
you get the principle.

And don't forget, there are plenty of group leaders out there who are
just plain dumb. You don't want to be in their groups anyway. :)

Jyzan