Soloing the fel Saberon rare Soulslicer in Fang’rila in WoW was surprisingly easy on my lvl100 Human Hunter in BM spec, ilvl 655, ilvl 640 weapon, Portent pet (good mix of tanking + DPS, it’s a rare from Pandaria).
[Update: even easier with Guardian Druid ilvl 660 (weapon 695) with Paladin bodyguard, v6.2.2 Oct 17/15, very fast, flew right beside him and no other mobs aggro’ed, bodyguard Ilona was defeated late but easy finish.]
As a human she got 550 Saberon rep (10% racial bonus, Lvl 2 Trading Post) which can be gotten reportedly several times daily on a character for each solo-able rare (there are 4 Saberon rares, likely 3 are solo-able), plus 27 rep for each of several of his minions, plus fel apexis shard from the rare for Order of the Awakened rep. Makes Saberon rep go much faster.
Most rares in Tanaan respawn roughly every 30 minutes.
Soulslicer is at the east end of the lake in southern Fang’rila, north side. He is on a little hill surrounded by about 6 lvl100 Elite fel minions. He is lvl102 elite. One of his minions pats around left front of him.
I take a while in this gear taking down the ordinary lvl100 Elite Saberons, and with freezing trap I can handle at most 2 at a time or it’s FD time. So I started on the hillside path that goes up into the mountains south, well to the right of the rightmost (facing them from the lake) minion, put pet on passive, pulled the mob to me then Kill Command and the normal single-mob rotation (no multishot or AoE Barrage or explosive trap). After him I took the next moving west, then the pat mob third. I took the pat and the next mob left of him from the lakeshore.
After 4 minions the east-most had respawned and I was concerned that the others would shortly also, so I went for the rare by Kill Command-ing the pet right onto his mound. Oddly enough the remaining minions ignored their boss. Soulslicer was an easy battle from range, very little damage to pet or hunter (a few hits for 19K but with Glyph of Healing both pet and hunter heal at 5K per tick), took a bit longer than a regular 100 Elite Saberon, a bit longer than soloing the middle ranked summoned arena boss for the weekly quest there.
About mid fight he summons a big brute 100 Elite which comes for the Hunter; I froze him in a trap, finished the rare and then easily finished the brute. I did use my summon Garrison troops ability during the rare fight which does usually aggro other mobs, but I was able to easily loot the rare and brute before FD (glyphed so pet feigns also) and waiting for the minions to reset positions before leaving via the lake in camouflage.
I have not tried Gloomtalon as he stands well back in a cave with about 6 minions several of which are up on high ledges. Others have soloed it easily by pulling left front 2 (including dropping Prowler) then right 1 and tackling the rare and a prowler together. I will try the solitary (and yellow, non-aggressive!) Krell the Serene as he can be pulled away from the pat aggro range.
I have been easily able to solo the middle (Rendarr) and lower rank (Akrrilo) Fang’rila Blackfang arena bosses for the weekly quest, have not had to waste the claws for the high ranked one (Eyepiercer) yet. Don’t bother with the arena guys if you don’t have the weekly quest as they only give apexis crystals and no rep.
If you are doing Saberon rep solo for the Draenor Pathfinder flying achievement, a rare or two daily will greatly shorten the process.