Thank you for such an amazing, in-depth, insightful answer, really amazing.
I was kind of in a rush to try this out so I built this before I saw your answer, which happens to not work out as well as my previous comp (which I realize now was pretty good).
So I mixed both of them and I'd like your input, here's my thought process:
Hydreigon
Jellicent
Ferrothorn
Conkeldurr
Tyranitar
Excadrill
now this is my first attempts at building teams. I've never played pokemon competitively so I'm really open to all input guys. I did, however, compete in Starcraft 2 and Starcraft Brood War and understand basic strategy in games of all kinds.
Reasons why it's not currently working:
Lot of physical walls that counter ttar, that I don't have an answer. Fighting OWNS me, as you pointed in your post. Yeah Ferrothorn is AWESOME and with leech seed, can win forced 1v1 scenarios like no other, but you have to take care of those pesky fire moves or strong fighting STABs first.
Weirdly enough, U-turn and Aquat Jet, or even Bullet Punch has given me lots of trouble. Basically any priority move. I got farmed by a Cloyster Shell Smash with the item that lets it prevent 1hko. Actually a nice build I might copy.
So Ice, Fighting, and just lack of damage mitigation / redirect / absorb brought me to Jellicent. I actually bred a Reuniclus and tried to run taht and, although the Pokemon is amazing, it didn't fit.
Perhaps I should replace (my far than perfect IV) Conk for something else? Maybe Jellicent for Slowbro and conk for Chandelure or Gengar? I kind of like Chandelure but I read he's impaired by the sand storm.
Any thoughts moving forward?