I am sure many folks have said this but.
The drop rate of tuskarr fishing upgrades from special pools is abysmal.
The best two pools are prismatic leapers and Overheated lava pools. But even then, there is 5 spawn locations for prismatic in Ohnaran planes and three general lava areas in waking shore that don’t spawn overheated often enough.
Maybe buff the drop rate a little so I don’t have to sink 10+ hours and trying to fish these item.
Or put them in the tuskar tackleboxes at the same drop rate as the coins.
Co-sign. I’m at 20 rep with the Tuskarr, which means I’m eligible for all of the equipment upgrades. To date, I’ve pulled one (1) Draconium nugget from frozen or lava pools for the first upgrade to the nets. That’s it. Nothing else for either nets or harpoon and I don’t know how many hundreds of tuna, leapers, and threshers I’ve pulled out of them.
lol it gets worse, first net upgrade is 3 nuggets, do that and you need 6 nuggets to get and upgrade!
Had most luck in Overheated Magma Thresher pools. So far 5 total nuggets.
I have all my fishing gear fully upgraded. The harpoon is useful - you can solo farm the elite lurkers. The net doesnt make a huge difference. I was fortunate to be on a server with not a lot of interest in fishing and spend time in the best area for overheated lava pools with usually no-one else there if I went early in the morning before work. You get very few upgrades from ice pools - i got a few from fishing nets.
Howdy, read over on WoWhead fishing guide they got a Draconium Fisherfriend and enchanted it with perception. I got one from the AH and started to get the items at a slightly better rate from those Ice holes and the Prismatic leaper spots. Hope this helps.
Amusingly, I have gotten some of the blue rarity items before I got my first and only Draconium Nugget. And since then, I haven’t gotten anything else. This slot machine sucks. 
I had completely forgotten about these upgrades because in the last three months and fishing in thousands of pools I have not caught a single item needed for the upgrades! I only remembered them because I accidentally clicked on tavio and saw all the upgrades. I asked in chat if anyone had managed to do any upgrades and got two people telling me the system has been broken for months,
Why did they bother putting this in the game if they weren’t going to bother keeping it working?
What’s annoying is the imbalance. I must have 20 of the wire and only a couple of the others. And one of those the fisherman says he would trade something for even though I still need more. I would love if they were able to be traded or made by a profession.
At one stage I was getting a few upgrade items when fishing in the overheated pools but then one week they suddenly stopped being fished up and I just decided to stop.
Haven’t been back in months.