Interesting topic, Skuj.
Two I can think of are:
Steve Holman in 1500m in (I think) 1996 Olympic Trial. He was something like 6 seconds ahead of the rest of the field and clearly THE favorite. But the thing about him was that he can't really sprint. I remember watching that race with a couple of friends here in MN and, naturally, we were all rooting for Holman, being a Minnesotan. He was in the lead but not in command. A lap to go, he was still in the lead but basically he was pulling everybody along. I still remember, this older lady was particularly excited and screaming for Steve and I was saying, "O-oh..." It turned into a mad-dash in the final 100m and, I think, he finished something like 6th and had no idea what had happened. Someone that superior with no kick should have going into the final lap with a comfortable lead and coast in. It doesn't matter if your PR is 20 seconds faster (in 1500), if you can't sprint and if you're in a mad-dash situation in the final 100m against people whose PRs are slower than you but CAN sprint; you're in trouble.
Bob Kennedy in 2000 Olympic Trial 5000m final. Before the start, it was reported that he figured he was not in his top shape so he approached Adam Goucher to share the lead the first 3k hard to shake everybody else out. Goucher decline but I thought, what a domb idea!! So he figured he's in a decent shape to push 3k out of 5k so he would make the race out of it in the FIRST 3k of the 5k race??? What the heck!!??? With his reptation, he should have walked in the first 2k, hoping everybody else would bunch up behind him THEN make the LAST 3k a hard race. Lo-and-behond, he took off at the start and, he was correct, he pushed the pace up till 3k and faded. Unfortunately, the race didn't end at 3k...
This one is not necessarily "a" race but, in my opinion, one of the worst master bad tactician is/was Tiffany McWilliam. A very good runner and, in my opinion, could have been much greater. She always seems to take the lead about a lap to go and fade in the final 200m. That tactic might have worked in college but never worked in post-collegiate level but she seems to have employed that over and over and over and over... A several years back, when our daughter's Japanese cousin visited us, they would play basketball together. Our daughter was playing basketball for AAU and we had a hoop by the garage. They don't even have a garage in Japan and he might play baseball in the playground but not basketball. Naturally, he wasn't as good. We were jokingly (this is kinda mean) calling him "safety shot" because we knew he most likely would not make the shot. Every time I saw her take the lead a lap to go, I remembered him because, it's like "safety sprint" because we knew she was going to fade about 200m to go...and she almost always did. I just wondered why she, and her coach, kept employing the failing tactic... I don't think I ever saw her winning a race, employing this "tactic".