[video=youtube;idTyV5HnU1c?t=22m49s]http://youtu.be/idTyV5HnU1c?t=22m49s[/video]
At 22:41 in this video you can see Hamstring and Crippling Poison being up at the same time. At 22:45 you see it from the druid PoV as well. Video is from december 2006. You can also find it on wcm.
another video:
http://www.warcraftmovies.com/movieview.php?id=31177
at 9:02 you see Concussive Shot and Hamstring stacking
at 22:57 you see Curse of Exhaustion and Crippling Poison stacking
at 16:48 you see Frost Trap and Crippling Poison stacking
at 21:30 you see Frost trap blocking Wing Clip from being applied
What im trying to say is that your video seems to indicate that only 1 slow effect can be applied. This is normally correct, but there are many exceptions of cases where 2 slow effects can be applied at the same time.
When i say stack, i don't mean that their effects are combined ofcourse. But if both are applied to the target then that means that abolish poison would not take him from 70% reduction to 0%, but from 70% and down to the hamstring at 50%. - this is quite a big difference to oldschool pvpers who im sure would appreciate these details. After seeing your videos and the seeing the transparency in your bug-reports im impressed at your level of ambition for the server and so i hope this comment don't come across the wrong way.
If you'd be interested i would be able to elaborate on multiple of these exceptions (with video sources obviously), as i've done a lot of research on this specific issue on another private server. If this is of interest, then send me a PM