Took me a while to track these down on the site, and thought I'd repost them here to save anyone else the trouble...
- New Hot Zones! With this patch the old hot zones have been reverted to their previous values and a new set of hot zones has been selected! The following zones are now the "Hot Zones"!
Level 20: Swamp of No Hope
Level 25: Overthere
Level 30: Timorous Deep
Level 35: Emerald Jungle
Level 40: Dreadlands
Level 45: City of Mist
Level 50: Skyfire
Level 55: Karnor's Castle
Level 60: Veksar
I know it is a different site but Allakhazam has the hot zones listed.
If you would update it all the time, I would sticky this post for you
I can keep an eye out for hot zone updates.
December 2006 Hotzones
25 Unrest
30 Tower of Frozen Shadow
35 Lower Guk
40 The Hole
45 Chardok
50 Sebilis
55 Grieg's End
60 Cazic Thule
65 Splitpaw
You are missing (from the latest list):
Level 20 Kurn's Tower
I suppose I ought to point out that the level ratings are meaningless; anyone at any level will get the zone wide exp bonus applied. It may also be obvious that a zone which used to be really bad experience, for any of many reasons, will still be bad experience, just not quite so bad.
Also, the last two sets of hot zones, as posted above, had permanent changes made to them - new mobs and mechanisms, and new drops. The June '06 set have some extra zonewide random items, plus a "call for help" behaviour, so that when a mob is about to die, you will see the call for help message, and an extra mob will come running in. The December '06 is that a mob at 20% has a chance of changing to "an unmasked changeling", which looks like you, and will drop an augment. There are also new rare named mobs with new drops (but I am not entirely sure if this is just the Dec set, or the June set as well).
These changes will remain when the zones are no longer hot.
Zones known to be lousy for XP'ing because mobs are too hard for what they give are not necessarily equally as bad as hot zones. It just depends on the dev realizing this and adjust the ZEM accordingly. CT is a good example: First time it was a hot zone the XP went from dismal to lousy but this time the ZEM really got a nice bump. 8-)
As for the changelings: NPC's make a check to see if they are a chengeling. The check happens within 5 seconds of getting to 50% health, so watch it if you are dps heavy for a zone and just want to farm an aug. If you drop mobs too fast some will not even have gotten around to perform the check.
Yes, the interesting thing to realise is that most (all?) devs aren't as clued about about zones as most players. We all knew that CT and Paw sucked, and why, and probably most had a good idea about LOIO and the Grey; but it took a couple of threads with devs asking questions on the EQLive forums for them to notice and make changes.
As a minor counter example, the Hole was great experience before hot zones (way, way back to the first producers letter where they mentioned it), and as a hot zone it's even better :-).