I've not tested WHS yet, but assume that the windows media connect part is the usual one, as found in WMC for XP.
I have a pretty nice library of music (15000 tracks), but i'ts not unusal now.
After trying many UPNP servers, i ended using twonky music server, because you can customize how your devices will show your library. It's not possible with WMC.
The UPNP devices are very different one from another ; depending on the remotes, you may find it very hard to find THIS track of THIS artist !
Any plan on improving Windows Media Connect in WHS ?
As it is one of the 4 pillars of WHS (shared folders, backup, media library, remote acess), I think that it's an important question.