I wonder what people mean when they say "This is not a breed for inexperienced owners." Do they mean your "typical" first-time owners who have not researched the breed or even how to care for a dog? The kind that think that walking Fido for one day a week is good enough. Is that what inexperienced means?
Inexperienced in the terms of the Malinois, as you mentioned that thread, is a person that has never trained a working dog before. You can have had average pet dogs for your whole life, and I still wouldn't suggest diving into a Malinois as your first working dog, if you start with a good one that is. But my assumption is that you always try to look for a good dog, you don't intentionally go out to buy a crap dog because he'll be easier, that would be silly. If you want easier to handle then get a good dog from a breed that is less nutty
I'd compare it to giving a 16 year old a 400 horsepower Corvette as his first car. He's going to make mistakes, either he's going to ruin a perfectly good car or he's going to get himself injured.
In terms of a GSD, I wouldn't give Will Rambeau's Czech dog Fetz to a first time handler, but there's lots of nice working line German Shepherd's out there that would be appropriate to someone with little to no experience with working dogs.
To me a first time handler needs a dog that is submissive to the handler, willing to please, driven enough to make training easy, but not so driven that the dog is difficult to handle. Hard enough to not shut down from mistakes and short tempers and the abundance of corrections that first time handlers think a dog needs, but not so hard that it detracts from the "will to please." Ofcourse, if you are a very soft person that doesn't often get impatient or short tempered then look for a softer dog. But soft doesn't always mean easy to train. The overall traits of the dog all need to be in balance or you will end up with a soft dog with no will to please and too little drive
If you're looking for a puppy then stack the odds in your favor with the breed that most suits that description. Lots of them do, but it also depends on the individual breeding, so don't go entirely on breed generalizations.
If you're looking for an adult then breed is less important than the dogs temperament. You could probably find yourself a Malinois with that temperament if you looked for it in an adult, but I wouldn't go to a top French Ring breeder and tell them you want a dog like that, because the odds are not stacked in your favor.
Out of the working breeds, your best bet is probably a German Shepherd, but choose the breeder carefully.
As for what traits make a dog unsuitable for a first time handler, since you mentioned the Malinois thread, go look there, I posted some traits that many Malinois owners will be able to relate to
Generally, the amount of energy they have is the least of your worries if you have a good working-quality dog.