That doesn't make them scary. It falls to the same problem that Star Trek: The Next Generation fell to (after a few seasons), and that is that stuff gets upplayed, we get told that these things are scary, but they aren't actually presented as such. Let me give an example from TNG, something that happened again and again: To show how scary and strong an opponent was the scariest and strongest TNG good guy was pitted against them, and lost. This was Worf naturally. The main problem with that was that afte a while this had happened enough times that Worf was suddenly not all that big and strong, after all pretty much any opponent that wasn't another Klingon involved in some political scheme, could beat him with a backhanded slap.
The same applies to the Wraith just the other way round. They are in fact quite scary in the first season, when the Expedition really can't match them, partly because they are still only encountered in small numbers and are still rather unknown. But soon they become a targetdummy and they only 'win' when the main characters are decidedly stupid, and before they can take advantage of that they are kicked in the nuts by an angry Expedition member. Eventually they simply fail to be scary because we have seen the resulting conflict many times before, and that is an overwhelming victory for Humanity. Humanity with a lack of power, a lack of advanced weapons and vastly outnumbered. The Ancients suddenly don't seem all that powerful either since they got defeated by these idiots. Eventually it is finally shown that The Ancients were in fact pretty dumb in dealing with the Wraith, they never applied the proper will to fight them until it was too late.
So the Wraith are not scary, they get defeated far too easily and far too often. Michael's hybrids on the other hand are significantly better, as they continually defeat their enemies, often they even win in defeat. As a result they appear vastly more dangerous, should Michael ever get enough numbers on his side (and we are even shown what happens then). The fact that the Wraith are borderline Goth doesn't exactly make their dangerlevels increase. It could be somewhat unnerving had they been cunning, but they rely on brute force, a style that doesn't fit their fashion.
In the end I was considerably more scared by the Genii because of their ruthlessness, persistence and intelligence, three traits the Wraith lack (save Todd of course, had more Wraith been like him I could have been more impressed). And before you call the Wraith ruthless, I have to say they aren't, they are bound by their nature, they appear incapable of actually using their 'scariness' or willing to sacrifice enough to defeat Atlantis. The Genii are willing to expend almost any resource to do that, friend, foe or even their own. That makes them unpredictable, and also quite a bit more successful at waging war against Atlantis.
So if you want Wraith for SotSII, I would say the Zuul serve a similar function, retaining the unpleasantness of the Wraith (consuming sentients in horrifying ways) but none of the stupidity or comical effect.
Every time you use 'fluff' for lore a Kerberos developer dies. And they are already an endangered species.