I've been using double priority Khan lately. And it is soooo powerful. Silk Scarf Double Edge nearly 2HKO's Weezing. I could easily see it being the next suspect test.
Khan is pretty viable in NU's current state, but is by no means broken (especially compared to buskenpass/sigilyph).
Besides, your point about weezing is sort of flawed, because:
1. While many of the previous suspects have been banned partially for this, just because {insert relevant defensive mon} can't switch in, doesn't mean "autobroken". Think BW Hydreigon, or many of the Megas (well, except Mega Luke, but what really made him broken was versatility) that have 1-2 switch ins, but many ways to check it.
2. Weezing isn't the ONLY relevant wall (Vileplume, Granbull, and Tomb say hi), which most are down here due to lack of recovery.
VS defensive Spiritomb (do people run Def investment or SpD investment?)
252+ Atk Silk Scarf Kangaskhan Double-Edge vs. 252 HP / 252 Def Spiritomb: 156-184 (51.3 - 60.5%) -- 90.2% chance to 2HKO after Leftovers recovery
Even with Specially Defensive Spiritomb, Tomb is 2HKOed (under 1 layer of spikes or rocks) and proceeds to burn it.
Proof:
252+ Atk Silk Scarf Kangaskhan Double-Edge vs. 252 HP / 0 Def Spiritomb: 195-231 (64.1 - 75.9%) -- guaranteed 2HKO after 1 layer of Spikes and Leftovers recovery
(Crotomb survives and can stall it out, but why are you even using Crotomb against Kanga (or any normal type in general)
VS Vileplume:
252+ Atk Silk Scarf Kangaskhan Double-Edge vs. 252 HP / 224+ Def Vileplume: 171-202 (48.3 - 57%) -- guaranteed 2HKO after 1 layer of Spikes and Black Sludge recovery
Same thing as Spiritomb (similar output), although Vileplume can only really Sleep Powder it.
VS Granbull (probably second most relevant after Tomb)
Atk Silk Scarf Kangaskhan Double-Edge vs. 252 HP / 232+ Def Granbull: 123-145 (32 - 37.7%) -- 93.5% chance to 3HKO after 1 layer of Spikes and Leftovers recovery
(take it with a grain of salt though, Granbull can't really do much against Kanga.
However, you didn't mention what the set even was (Double-Edge/Fake Out/Sucker Punch/filler?), so idk if it actually KOes after Fake Out, and did you use spikes support?
EDIT: I didn't mention Ferroseed, so unless you run fire punch (which I doubt) you're screwed.
EDIT2: it wasn't right to make a TL;DR post just for something like this wasn't it
TL ; DR, Kangaskhan is not broken, especially compared to Buskenpass or Sigilyph, and it barely even fits the bill of "not broken because it has quite a few checks, even with no switch ins"