Redanian Knightcan be described as a multi-purpose card, you can utilize it in a number of ways. One way is using it as an initial body on the board, and strength play. Another way to use the card is as an "anti-weather" tech card. It can also block weather effects from hitting your lowest strength units on the row it is placed, but this generally applies to Fog and Ragh Nar Roog only. The card having agility now allows for greater utilization.
Redanian Knight shines the most in Dagon matchup since they would 100% play fog. Well redanian knight is pretty amazing if the opponent plays any kind of weather. And after that it's just a basic 8 strength 2 armor minion which is terrible and they doesn't have any kind of synergy with other card except the armor removing cavalrymen. But well sadly there's no one playing that kind of deck right now.
Armour deck is a thing. Lifecoach uses it, I saw a few people at rank 18 using it. I don't see the appeal of it. But that 4 armour guy that gain 5 plus the armour remove guy and that potion that gives you 3 armour works really well if you get the combo off.