Why has Rend Blackhand never been a thing in dragon decks? I see him sometimes, but never in recommended lists.
Look at all the decks that are being played right now and count the number of Legendaries in them.
Shaman decks? Not a single god damn one.
Hunter decks? Maybe Huhuran but not really. Essentially no Legendaries in Hunter decks.
Druid decks? Maybe Fandral, maybe Twin Emperors, usually Bran... none of which are godlike targets for Rend. Of course there's Cthun but the match is usually over by then.
Warrior decks? Control Warrior has lots of targets but that has been less prevalent. Cthun Warrior has very few Legendaries outside of the two Cthun ones and Grim Patron has a single Legendary in it and the game is usually over when it gets played.
Warlock decks? Zoolock only carries Brann...Control Warlock is garbage right now.
Mage decks? Tempo Mage decks have very few Legendaries (usually only Antonidas but that's being played at the end when the game is being decided) and aside from Thaurisan isn't not a big deal to Rend their other Legendaries.
Rogue decks? Based targets are Van Cleef and Malygos. Malygos you will never have the chance. And Van Cleef usually comes out very early in the game and far before Rend is a factor.
Priest decks? Ironically Dragon Priest is the best target for Rend Blackhand because it can snipe Chillmaw, Ysera, Nefarian or Chromaggus. Control Priest on the other hand runs very few Legendaries these days but it can snipe Ysera though so that's good I guess.
Paladin decks? Aggro versions don't run any.. and it's garbage trying to snipe Nzoth Paladin Legendaries. Snipe Sylvanas, they steal Rend. Snipe Tirion and they get a weapon that kills Rend. Snipe Cairne and it still leaves a 4/5 body that kills Rend.
This was even worse when most decks only carried Dr Boom. Snipe Boom with Rend and then get your Rend killed by a single Boom Bot... wow dat value. BGH was a better option in that case. Honestly Rend Blackhand was only somewhat relevant at killing Emperor Thaurissan at the spot and that card is less common these days.
The stats really kill Rend Blackhand, 4 HP for that expensive of a minion is really bad.