Gothmog killed Fingon, Glorfindel was killed by a Balrog.
Glaurung was killed by Turin Turambar.
Anyway, to name another uncool character : Fëanor and all his sons... I know that without Fëanor there would be no Silmarils and as such the whole history of Arda would be different, still he's a terribly arrogant and ambious character.
And his sons r even worse, they're as arrogant and ambious as their father, but instead of wise, they're stupid.
How they attacked -and killed- Dìor and Nimloth and killed them... and later attacked the Mouths of Sirion just to get that stupid jewel... well they're not very sympathetic.
Give up the Halfring, she-elf...