It's not crowded in the least. On a warm September day I was the only visitor, other than a bridal party who had bounced their way along the road to take photos among the ruins before scooting back to the reception.
The place compares favorably to Butrint because it's dry. You can walk in among the ruins and never have to worry about slipping in the mud.
Imagine watching a performance in this theater. It must have been tough for the performers to compete with the view from the seats out over the valley.
Another endless view over the mountains of Mallakaster. .
If you want a second opinion on Byllis, here's a great article.