I have found that kopete is abandoned. Yahoo IM does not work
any
more. the IRC plug-in has been absent for far too long. queries about
problems are not getting replies

pidgin lacks the video chat but all the protocols I require work.

can you support the statement that gnome is moving to empathy?

Reply: Kopete is less of a one stop solution now. There are several KDE IRC
clients. You have singled out one area where KDE seems to be splitting off.
Quassel and Konversation seem to be the clients of choice for KDE with the
former being the newer and the one that will survive when KDE 3.5 is put to
rest. I have heard of past problems with Yahoo, but no current ones. My Yahoo
account connects fine. Don't use username@..., but username only.

This is a very active area of development due to all of the convergence of
technologies. Telephony and texting to mobile phones is all of the rage now. No
telling where things are headed. Everyone is jockeying for position and this
brings inevitable problems with one stop platforms staying current as standards
for the various parts are changed.

Empathy ties together several clients. It includes IM and VOIP built in. It is a
GNOME project whereas PIDGIN is not. It was included in Gnome, but it is not
their baby. So it isn't whether Pidgin will be replaced by Empathy. It has
already done so because Pidgin was not Gnome's to begin with. Whether distros
choose to use Empathy from Gnome or Pidgin is the question. So far Ubuntu has
kept Pidgin, but I don't see that continuing as Canonical works closely with
both Gnome and KDE and tries to keep things tidy. Pidgin runs on Windows, so we
know that is bound to work against it in the open source community.
Multi-platform IM clients are few and far between and Pidgin or Gaim's success
has been having the most features and being the most versatile. Whether it can
sustain this in Linux is open to debate.

Wikipedia:

Empathy is a re-usable collection of Graphical User Interface widgets for
developing instant messaging clients for the GNOME desktop. It is written as
extension to the Telepathy framework, for connecting to different instant
messaging networks with a unified user interface.
Empathy has been included in the GNOME desktop since version 2.24.It includes a
sample client with a similar overall look and feel to the earlier Gossip client
for Jabber/XMPP servers