Criticising the opinion that says there was a lack of playtesting in the face of actual errata and faqs would seem contradictory.
The whole point of plattesting is that you don't then need to fix things afterward (assuming such fixes work).
Noone has suggested playtesting is, per se, easy. But it can and should be done. If you choose a fairly in depth crunchy game design then you must accept the requisite amount of playtesting - and it's hard to imagine a shortage of volunteers.
If the issue is time, well perhaps adopting such a heavy duty schedule (3, soon to be 4, game lines) then you really should have known better. If you don't have the resources to put out Xenos Compendium within even the first 2 years of the game's existence then you are not doing your job and have probably not got enough people on the case.