You can just see the goals set behind LoD & the consequences a rushed release or not will have.
A rushed release without testing (only 1 week on PTR with 2-3 guilds testing nights) will cause later endless spam, disappointment & arguing in game & in forums and it won't meet the expectations set by the Stuff itself on LoD.
Postponing release by the number of days needed, enough to test on PTR & fix & polish content will result on some people crying & waiting a bit yes, but on then long run & good release, all will be satisfied & LoD will meet the goals set, which is the whole thing.
For BC it's acceptable to have bugs, not fixed major problems as nodes, no SWP or BT but atleast take care of WoTlk for god sake.