90s:  The Adjective-less X-Men
Cyclops with tons of pockets and a pocket protector on his chest held there
by a yellow g-string bra.
Jean Grey with paddings around her thighs (thigh cheese?).
Psylocke with random bandages around her legs.
Magneto began to have holes in his gloves and boots around this time.

00s:  Wild S.C.A.T.!
Zealot had giant boomerangs on her back even though she uses swords.
Grifter wears a woman's red undie on his face.  I hope he washed them first.
Why is Spartan wearing mask even though he's not even from Earth and not
even alive and doesn't have a secrete identity?
Cute green ponytail on Warblade.

10s:  The 52!
JLA's militaristic look with the v-neck collars does not work because they
didn't get together first to decide what they want to wear.
How is Aquaman breathing if his collar is covering the gills on his neck?
Does a person living undersea need gloves and boots at all?
Isn't the Flash protected by the Speed Force?  So he doesn't need thick
soles or wear shoes at all.
Random lines all over everybody's boots!  It just looks bizarre and
non-functional.  This takes random seams to the extreme.
You can't tell that Cyborg is a cyborg just by looking at him so let's put a
big letter C on his chest.

I'd say that Steve Lightle is my favorite costume designer.  His redesigned
a lot of Legion uniforms in his short tenure and everyone looked fabulous.
Before him, I never knew that Shadow Lass was wearing a skullcap.  Even a
simple one like Shrinking Violet's mini-skirt really stood out.  Before him,
she was wearing a weird leotard.  Surely DC could bring him back on a
non-monthly basis like what they are doing with Van Sciver.