Understand where you're coming from buzz... Let me make myself clear, I'm not adverse to buying in any of these areas if it's the right property. For example in West Melbourne there are some great properties on Adeney.
The problem is that West Melbourne and North Melbourne are very commercial and the zoning is an issue. It's not an area that a novice can easily find good property in and thus advising first time purchasers to look in such areas may increase their exposure to downside risk unnecessarily. Therefore the areas should be advised against in favour of the suburbs that increase a purchasers chance of growth while mitigating risk.
In any case I'd buy in Richmond and Port Melbourne over West/North Melbourne any day... Their historic and projected growth is much better and they're now much more diverse.
Also, as a side note only 3/10 suburbs in Melbourne have performed recently... now is the time to be very very careful with where you're looking.