Note - Please say if you are ranking the normal or hard modes. I am ranking the heroic fights only, not normals. this is all from the role of a ranged dps.
1) Ragnaros - Satisfying fight. Great variety, great strats, then the fight takes on a completely new dynamic with LEGS (sadly i miss triangle stacking). The only fight that i would rank as epic
2) Valiona & Theralion Fight that very nicely tested stacking and unstacking, with good rotation clipping, multidotting, and CD management mattering a lot. Rewarded the good dps.
3) Cho'gal - I like fighting chars with more lore behind them, combine that with good multi-phase fight and a good difficulty. Rewards people for not being stupid with environment, yet does not auto-wipe the raid for screwing up(only complaint is the worship is annoying when a warlock fears you across the room and forgot to glyph it).
4) Zon'ozz - Not sure why exactly, but I loved the fight. A good twist on heroic with how P2 works, and breaking up the monotany with well spaced Movement and killing tentacles.
5) Atramedes - good fight for testing tons of movement, while not being to severe with small screw ups.
6) Baelroc - I loved this tank n spank with a twist fight. The downside was the dps requirements pre-nerf combined with 2 of your 3 heals (yes you 3 or 4healed it in 25 early on) getting the link.
7) Sinestra - Wrack and unaware tunnel visioners who got a shadow cutter was painful, but the fight was still dynamic and fun.
8) Madness of deathwing. Fight had a hard time tuning itself, with most of the fight being dynamic, but undertuned then 2 extreme spikes in difficulty(sub 5% and 4th platform) For the endboss, was overall to easy, and I was highly disappointed that you dpsed static tentacles or deathwing.
9) Ultraxion - tank n spank fight, but the fading light is a meh mechanic imo. Soaking the booms though was a nice feature.
10) Alysrazor - flying was all number maxing, but dpsing on the ground was a good bit of fun. Really stressed your raid awareness and good movement if you were dpsing on the ground.
11) Majordomo - not the best fight when you are a ranged without an instant - get me out of here- ability. Had some interesting raid mechanics and movement though.
12) Halfus - another fight that could of been ranked higher if only it was tuned better.
13) Omnotron - excellent awareness fight, though it relied a little to heavily on interrupters and having to stop dots early is always painful to avoid breaking those shields.
14) Shannox - good fight, my knock on it was it was woefully undertuned
15) Mediocre fight, badly undertuned
16) Maloriak - fight was a mediocre one. Combine that with having to stop dps so you can get a green phase to clear adds (which basically was punishment for being good dps) and it was boring and dull.
17) Gunship - Fight was one of extremes. In many ways it was nice as it rewarded people for smart movement and min/maxing your multi-target moves. it was utterly painful when fire decides it is going to cover the whole ship when you reach p2 with the ship at 38% and the gnomes wont put it out. the RNG on the fire....awful. Nearly every wipe was due to something going wrong due to fire.
18) Nefarian - P2 was .....gah when your resto shaman is your best interupter. Combine that with P3 being all about 1 person learning to kite adds....
19) Beth'tilac - Fight was fairly annoying to learn as its 90% teaching 3 people to soak broodlings while soaking little spiders. Worst part is that slow from the broodling explosion then 3 hightail it for the middle soaker at once. Once you get the fight down, boring as not uncommon for everything within 40 yards to be dead.
20) Yorsahj - Any mana user with a 3 min CD on their mana talent understands the frustration of trying to maintain competitive dps with several blues in a row.
21) Magmaw - I kite. Pretty boring to kite for the whole time. Not hard, just boring.
22) Ascendant Council - frost orb is on "player that likes to tunnel vision". Probably the worst fight for that 1 out of 25 person causing a wipe. Combine that with the annoying spread and shifts between ground and air....
23) Hagara - pillars not wanting to light. both healers getting ice blocked. insta-gibs from the stacking ice buff and lance. A fight that wasn't that interesting combined with RNG.
24) Conclave of wind - Guess what - I kited the adds. Anyone who dislikes kiting and was forced to kite this fight understands.
25) Chimaeron - I love fights that cause tank gibs and punishes dps who lack threat drops. Combine that with the miss chance from ooze screwing up your rotation very unpredictably....
26) Rhyolith - getting dps to switch feet collectively and cleave just right is pretty frustrating. combine that with having to teach the RL how to call out steering (which dps to switch) and the fight was a pain to learn at first, before becoming a snoozefest once people learn it. there just was no middle ground.
27) Spine - Stack arcane mages and die a few hundred times to P3 bloods.
28) Al'akir - double squall lines crossing and wind blast converge on tank heals at once. Hated the RNG and sheer difficulty of this fight on 25H