With no secrets, he's a 5 mana 4/4, which is abhorrent. With one secret, he's a barely better Silver Hand Knight, which still isn't constructed viable. You must have at least two secrets in play for him to even be worth looking at.
Compare to Petting Zoo in hunter. With no secrets, it's weak, but not altogether abhorrent. With one secret, it's well above average. With two or more, it's fairly backbreaking.
Seems like an absolutely bonkers card but I was looking into the meta and it seems no Secret Paly list runs him.
Someone explain this insanity to me.
Most of these lists I see only run 4 secrets or so. You don’t have enough active at once to really make an impact. On top of that, Oh My Yogg is so OP I can’t imagine wanted to turn it into a 2/2. The prevalence of devolving missiles might also play a factor.
Because it's cost is relatively high in a secret paladin deck so you wouldn't keep it in hand, so you would have to somehow draw it before turn 5 and even then you probably wouldn't have many secrets by the time you play it. Basically you barely get any value from playing it and it also temporarily disable your secrets disruption for a board which could be somewhat cleared easily
Because Secrets are what makes Paladin powerful. I would even argue that they are the OP part of current Paladin.
Using Smythe removes Secrets (yes, only temporary, but even 1 turn is crucial against decks like aggro, and you'll want your Secrets active to protect yourself against spells or attacks directed to face).
Sword of the Fallen got nerfed > people play fewer secrets in the deck because you can only cycle 4 instead of 6 > Smythe isn't worth playing anymore.
Simple as that. It has nothing to do with its cost of clunkyness, it was a much better card before the nerf, there was a good chance your board was still full of secrets by turn 5, now you're out of secret by turn 3 in general. Sword of the fallen was the primary reason to play secrets in the deck, and the nerf hit Smythe harder than the actual sword, because Smythe needs the sword, but the sword doesn't need Smythe.
If you still commit to playing a full secret paladin deck, with 10-12 secrets and Crossroads Gossiper, you WILL get value from Smythe and he will be worth playing in that deck, but not in the current T1 meta deck.
It's up to you if you're a netdecker or a builder.
It's just not a good card. Turning your secrets into 3/3's may seem like a good aggro tool, but really you're just opening yourself up for your opponent to hit face for lethal without having to worry about secrets. That's why no one plays it. The secrets are more valuable as secrets than they are as 3/3's
1) He is slow. At 5 mana you often want something more impactful than dropping some plain stats on the floor that don't have rush/taunt or anything
2) Paladin secrets trigger quite easily, so you are unlikely to have more than 1 secret up there at the beginning of your turn. This means that to get some real value out of Smythe you might have to play 1-2 secrets first then drop him, making him even slower (as it would now be a t6-t7 play)
3) This might not even be feasible as Paladins don't run so many secrets anymore since the weapon got nerfed. Some of the secrets are good, but not that powerful that you want to have 8-9 of them in your deck. You want to have just enough that the weapon will consistently thin your deck and you can draw 1 card with this 3/4 minion.
4) Without any secrets up there, your Smythe and his 3/3s are very exposed to all kinds of removal (spells, trades...) which otherwise your secrets protect you from. It can even backfire big time if a Priest responds with a Soul Mirror, clearing your board and simultaneously copying your secrets (as Soul Mirror copies the deathrattles of the 3/3s) meaning you will now also have to play around them