There's so many examples of "they shouldn't have stuck with this guy" vs. "good thing they stuck with this guy" that I don't think they're worth much anymore.
But I think if you believe we have a midtable quality squad, expecting a new manager to come in and get anything better than midtable results is unrealistic. Frank is an experienced Prem manager who did extremely well at Brentford, mostly prior to every Prem club becoming gigarich. I think he at least deserves a season and a half to bring in his players. If we're still bad at this time next year, then we can have discussions to sack him.