I think you give too much credit to Speidi and not enough to the producers. It was the producers that created the twist that allowed Speidi to do their thing. The producers came up with the task where housemates were forced to tell other housemates some not very pleasant observations. Speidi only chose the 5 that would participate. The producers, according to Spencer, decided which conversations Speidi would view during their 4 hour hibernation. IMO the producers wanted this kind of season. That's why they brought Speidi in to begin with.
I think they tried last season, but The Situation had gone through rehab and was clean and sober. So, instead of the wing nut 'Situation', they got Mike. Luckily, Nana turned out to be the drama they needed.