I agree that this was the major problem, they couldn't do any challenges with real stakes (immunity/elimination) because two of the contestants had immunity for what felt like nearly 2 weeks. The cast was too small by that point because of the alexis/trayvon/alex b walkouts to actually remove someone without impacting content before FH2.0 - and the two immunities put them in a complete stalemate up until the final FH1.0 vote which was never going to be anyone but Mizzy.
They should've wiped the slate clean after the walk-offs, but then production would have had to face the wrath of the lion. Another alternative is to only make immunity last X amount of days, vote or no vote (but that'd still lead to cast bitching). It'd be better to remove voting entirely or be far more careful about how many people can have immunity. When 2/5 of the cast have immunity the resulting vote is almost a formality at that point.