Well in my view, I would not do any civil work until the age on 1 year at least. That's for sure! Until then, the dog is simply not mature enough. If you start civil work too early in life with the pup, he may not take seriously enough the task ahead and by the time he's supposed to be doing that, civil work would rather be just routine to the dog.
Obedience and correction... i guess one must be careful in how much of the two is applied on the dog through training, according to the desired target.
You can probably spoil the toughness in the dog, to some degree, again - if you start things too early in life. But I may be wrong, that's just what I think.. But then again, it also depends on how much rag work / obedience etc.. gets done regularly. An experienced trainer would not turn the dog into a robot (the dog undergoes very frequent training and loses the 'fun' part of it).
I'm curious to hear what others, with more training experience would have to say about this though... From my point of view, toughness and dominance are genetic and one cannot alter that just like that. That is also why I have second thoughts on the neurological stimulation etc...