I watched this last night and it was even worse than I remember the last series being. What on earth are the BBC thinking? The castles and costumes are decidedly late medieval despite King Arthur supposedly being around in the early saxon era. The 'blind casting' I can understand however the general standard of the acting in it is terrible, although I suspect the Royal Shakespeare Company would struggle to impress given the banality of the scripts. The story arc doesn't seem to be going anywhere; there is no sign yet of Uther dying so that Arthur can pull the sword from the stone, no knights of the round table on the horizon; nothing. Rather than the Arthurian legends we just get huge dollops of Lord of the Rings style dragons & the like.
Only worth watching for the eye candy Arthur & Merlin and the amusement value of a Victor Meldrew wizard.