Those bosses are now shared between realms with CRZ, so I have tested how many of them are available in EU English realms.
There are currently only 6 CRZ clusters: 2 PvE clusters, 2 PvP clusters, 1 RP, 1 RP-PvP. On RP and RP-PvP bosses are mostly available, but sometimes people do kill them. On PvE and PvP clusters bosses die within 15 minutes of spawning, often being camped by several players. Even Nalak is dead most of the time.
This needs to be fixed. There are too few of those bosses with too long respawn timer. When MoP was live it wasn't a big deal because each realm had their own bosses. Now there are only 6 realm clusters for all EU English realms combined.
For those who are interested in list of realms in each CRZ cluster (to farm rares or bosses in any pre-WoD zone), here is full list for PvE and PvP realms:
Code:
PvE 1
- Aszune / Shadowsong
- Azjol-Nerub / Quel'Thalas
- Azuremyst / Stormrage
- Blade's Edge / Vek'nilash / Eonar
- Bronze Dragonflight/ Nordrassil
- Bronzebeard / Aerie Peak
- Darkspear / Terokkar / Saurfang
- Doomhammer / Turalyon
- Draenor
- Emerald Dream / Terenas
- Khadgar / Bloodhoof
- Kul Tiras / Alonsus / Anachronos
- Lightbringer / Mazrigos
- Magtheridon
PvE 2
- Aggramar / Hellscream
- Chamber of Aspects
- Ghostlands / Dragonblight
- Hellfire / Arathor
- Kilrogg / Runetotem / Nagrand
- Silvermoon
- Wildhammer / Thunderhorn
PvP 1
- Burning Legion
- Darksorrow / Genjuros / Neptulon
- Dentarg / Tarren Mill
- Dragonmaw / Spinebreaker / Haomarush / Vashj / Stormreaver
- Drak’thul / Burning Blade
- Emeriss / Agamaggan / Hakkar / Crushridge / Bloodscalp / Twilight's Hammer
- Karazhan / Lightning’s Blade / Deathwing / The Maelstrom
- Kor’gall / Bloodfeather / Executus / Burning Steppes / Shattered Hand
- Xavius / Skullcrusher / Al'Akir
- Zenedar / Bladefist / Frostwhisper
PvP 2
- Auchindoun / Dunemaul / Jaedenar
- Grim Batol / Aggra
- Kazzak
- Outland
- Ragnaros
- Ravencrest
- Shattered Halls / Balnazzar / Ahn'Qiraj / Trollbane / Talnivarr / Chromaggus / Boulderfist / Daggerspine / Laughing Skull / Sunstrider
- Stormscale
- Sylvanas
- Twisting Nether
This list is current. Blizzard might change that any time. RP and RP-PvP clusters are obvious - all RP realms are in one RP cluster, all RP-PvP realms are in one RP-PvP cluster.