I'm going to say this just as a mourning ritual for me, but also as advice for others. When standard and wild cycles began, I kept my wild legends and epics just in case I wanted to play wild, but of course as new expansions released, being an impulsive person I started disenchanting some of them, the worst of them, but then it extended to some of the good ones too. When I realized I was at a point of no return I just went all in and said to myself, let's forget about wild and focus just on standard forever. My one and only golden legendary n'zoth was lost in between this mess and I miss it. Now that I want to go back it's too late, don't do bad like me.
Good luck in wild, I feel it can be more frustrating at times but you get to play with awesome old cards. But yeah I opened golden N'zoth at the time and that was incredible, I've never gotten one again.
This is why many players say not to destroy any wild cards. Even if you don't play wild they will eventually make you want to play it either casually or competitively. I personally would never destroy a legendary one even if it was bad.
Since i hate the standard format and wanted to play mostly wild i went another route.
I‘m a f2p-player, so i was missing some cards i always wanted. So i decided i disenchant all the cards of 2 classes i pretty much never play and dislike to craft most of the cards of my favorite one. It was the best descicion i‘ve made in this game. I enjoy it much more now.
For those who want it to know: i „deleted“ paladin and shaman to craft all the relevant and fun priest cards. And no, i‘m not a brain-dead res-priest player. I do fun homebrews :P
When I started playing as a F2P just 5 months ago I was disenchanting any card I didn't find useful at the time trying to get enough dust to craft one halfway decent deck. I don't even remember all the cards I dusted, I know there were at least 3 legendaries though and one of them was Lord Jaraxxus for which I feel really bad now (even though he is still unplayable)