I'd like to write a spoiler free review because the episode was so bad that if would go into specifics, it would end up in a rant. However, it perfectly reflects S4, which started out not too bad, but then devolved into an ugly mess. Even I as an amateur could pin point the problems of extremely lazy writing, poor planing and execution of the season long plot and a huge drop in quality around visual effects and stunt performances. It's so blatant, that messed up shots of some extras or stunt doubles are making the cut these days and aren't ending on the floor. It's "bad wig stunt guy in an 80's TV show" bad.
The S4 finale bottles all that's bad and gives you one more dose of it. Luckily it also provides enough closure and avoids any cliffhangers, so right now I've absolutely no reason to even be curious about S5.