I got a few under the radar ones...
Not an angle - but TEST in general.
Had the size, youth and athleticism. HE was really getting over, then the Steph / HHH angle happened and TEST... got buried? WHY?!?!!
What was the point in this? What was he buried for? He went to become a mid-carder and tag team specialist. WHY?!
He should've been pushed. He should've been part of this coalition against HHH and D-X (plus Big Show while tossed in there).
Undertaker as American Bad Ass
I personally liked it as a whole. I liked that we saw Taker be who he was. He really came into a more likable character since they couldn't decide if he was a mysterious character of the leader of a cult... but Uh, he just leaves for 6 months and we pretend he's "alive" again? Um, what? Have some angle where he's "resurrected" or something. Build a character to feud with him with someone who is a "Holy" figure first... Then Kane "killing" him in the end would make sense.
SUMMER OF PUNK
Okay, this likely isn't really under the radar... but this doesn't even need any explanation.