Arrow season 5 it's definitely a big improvement from season 4. It's right up there with season 2 and 3. For me season 2,5, and 8 go shoulder to shoulder as the best seasons of the show. This one goes big with the fight scenes, with new characters and with older returning characters, which a new menacing villain, with the crossover, and with an epic finale.
The dvd versions have all the episodes on 5 discs, but doesn't include the entire crossover just the 100th arrow episode which by itself is a great episode. I don't know if the blu-rays have the entire crossover. Overall if you're a fan of the show this is definitely one of the best seasons of the show.