I came here to say Eye and Curran. Both 1-5 AND STILL GETTING FIGHTS! THEY COULD END UP WORSE!
As for the worst of all time, there's literally been articles written about him: Kenneth Allen
http://mmajunkie.com/2014/02/one-mans-worst-fighter-ever-is-another-mans-band-aid
http://www.sherdog.com/fighter/Kenneth-Allen-13050
SPOILER ALERT
That article is a few ears old now, and he has not gotten better.
As for the worst of all time, there's literally been articles written about him: Kenneth Allen
http://mmajunkie.com/2014/02/one-mans-worst-fighter-ever-is-another-mans-band-aid
http://www.sherdog.com/fighter/Kenneth-Allen-13050
SPOILER ALERT
That article is a few ears old now, and he has not gotten better.