Another problem with generic magic in a Golden Dawn context is quite often the core of the system ends up being something that is not actually Golden Dawn.
The purpose of Golden Dawn is varied; but the working techniques are pretty much the same from Order to Order. In groups that take the generic approach this is not always true.
For instance, I know of one Order that basic working technique is "spirit guides." Golden Dawn traditionally has nothing against spirit guides (ignoring the political and PR statements concerning Theosophy), but it is not something that Neophytes are encouraged to dabble in.
In this spirit guide system, contact with the spirit guides is considered the crux of the system, with all the other techniques being optional. It should be the other way around in my opinion.
To understand the problem with the idea of making contact with one's spirit guide and ignoring the rest of the system, just think about this: How do you know that it is actually your spirit guide and not a demon (qlippoth)?
There is nothing wrong with making contact with your spirit guide; there is a problem if you have no way of testing and defending yourself against possible hostile entities.