In response to the OP, Zook did NOT have a 3-year plan, but a 4-year plan - you're missing the 1st year of his plan:
Year 1 - Lose big
Year 2 - Lose small (close)
Year 3 - Win small
Year 4 - Win big
Now, you may have thought Zook had a 3-year plan because his best year was his 3rd year, but he did completely follow his plan in years 1 & 2. In Year 1, his teams got killed and they had only 1 or 2 wins that year. In Year 2, while their record was still terrible, almost all their losses were very close. As Grunkie points out, for various reasons they outperformed in year 3 and then in year 4 they suffered underperformance and key losses, etc., etc. so Zook did not get his plan. But even in year 3, they had a number of very close wins that they could've easily lost.
Now, how's Brew doing vs. the 4-year plan? His results:
Year 1 - obviously most Minnesotans would argue this was a "Lose big" season because they were 1-11, but those of us who followed them know how many close losses they had and how easily the record could've been 4-7 to 6-6.
Year 2 - We were somewhere between a lose small and win small year. You could definitely see improvement, but for whatever reasons we just fell flat on our face against Michigan and Iowa.
Year 3 - Hopefully, we'll continue to see improvement. I think the team will be better next year, and I'd count 7-5 as an improvement if it means all the losses were competitive (and to a slightly tougher schedule than 2008).
Year 4 - I think the offense would definitely be at peak performance in 2010 with Weber a Senior and various other skill position players and lineman as Juniors or Seniors, but a huge portion of the D graduates in 2009, so it depends on how well Brew can fill in those losses.
And, while Brew controlled the game day execution in 2007, 2008 was his first year of truly having some of his personnel (and mostly freshmen at that). I don't know if Zook was hired early enough to recruit for his first season, but Brew only had time to scrounge up a half-dozen or so players before the recruiting deadline in 2007. And I don't think any of those guys are still with the team.
I support Brew for now - I like the talent he's bringing in, his positive attitude, his work ethic and on game day I've seen some errors, but it also seems like he's learning from them.