Let's look at this a little more closely, however. A large part of Willingham's problem was not simply his uninspiring 21-15 record (ironically, identical to Davie's .583 win rate) but ND's inability to show significant progress in the last two years.
Any single year's record can be deceptive. Lucky wins and unlucky losses can quickly swing a record one way or the other. In some ways, total season point differentials can be more revealing of where a team is headed.
Here are ND's total scoring margins going back to 1961:1961: - 7
1962: - 33 Kuharich resigned
1963: - 51 Devore interim
1964: +210 Ara hired, Near National Championship (1 loss)
1966: +324 National Championship
1970: +246 Near National Championship (1 loss)
1972: + 97
1973: +293 National Championship
1974: +171 Ara resigned
1975: +100 Devine hired
1977: +287 National Championship
1978: + 96
1979: + 46
1980: +120 Devine resigned
1981: + 72 Faust hired
1982: + 32
1984: + 60
1985: - 4 Faust fired
1986: + 80 Holtz hired
1988: +237 National Championship
1989: +238 Near National Championship (1 loss)
1992: +246 Near National Championship (1 loss, 1 tie)
1993: +212 Near National Championship (1 loss)
1994: + 62
1996: +226 Holtz resigned
1997: + 17 Davie hired
1998: + 80
1999: + 17
2000: + 86
2001: - 1 Davie fired
2002: +73 Willingham hired
2004: +17 Willingham fired
One thing that jumps out immediately is the degree to which coaching affects the team's performance. Ara made the most dramatic impact, but Holtz produced immediate results, even if they didn't show up in the record immediately.
In order for a major conference team to be seriously in the hunt for a national championship it requires a total scoring margin for the season of at least +200 points. Anything less than that, and a team is likely to be in too many close games and will eventually suffer an unlucky loss.
ND's 2002 team was a fine illustration of that point. After winning close game after close game for the first eight, ND let Boston College hang around and then seven fumbles allowed BC to escape with a 14-7 win. If ND had been the sort of team that routinely ran up 28-point leads on teams of that caliber, the result of playing badly and turning the ball over would've been a too-close-for comfort 21-14 win instead of a 14-7 loss.
So what does this have to do with expectations and whether Willingham was fairly treated?
Notice that even as recently as the tail end of Holtz's career, ND was regularly running up scoring margins that could've put in regularly in the NC derby and certainly in a position for major bowls. In 5 of Holtz's last 6 years, ND had a scoring margin of +145 or better and 3 times cracked the 200-point barrier.
Notice the immediate collapse of these margins starting with Davie. In the eight years of Davie and Willingham, ND never finished the season over +100. In fact, ND rarely poked its head over the +100 margin at any point in a season.
The high water mark for Willingham was after ND beat Rutgers 42-0 to go to +126, but 31 and 22 point losses to close the season brought that down to the +73 at the end of the year.
Davie's 2000 team got to +118 after beating USC to close out the regular season, but a 32-point loss in the Fiesta Bowl brought that down to +86.
So neither Davie nor Willingham were producing teams that were anywhere close to national championship caliber. Their 3-loss teams that went to bowls were not nearly as good as Holtz's final team that went 8-3 and didn't go to a bowl.
In terms of average scoring margin for a season, Willingham was actually the worst of any full-time ND coach since Kuharich. Willingham's teams averaged only +6 points for the season. By contrast Davie's were +40, Holtz's +168, Faust's +60, Devine's +130 and Ara's +210.
Even if ND's team this year had been, say, 7-4 with a +120 scoring margin one could say that progress was being made. But ND's very slim +17 scoring margin showed that ND was right about where it should've been at 6-5. The explanation that ND was two plays away from being 8-3 ignores the underside of the reality that ND only two plays from being 4-7.
If Willingham had taken over a team that was 1-10 and -180 on the season point differential (actually he is taking over such a team at the University of Washington), then getting to 6-5 and +17 in the third year would be rightly regarded as being good work that should continue a coach in office. At ND, however, Willingham took over a team that had averaged 7-5 and +40 for the prior 5 years. Under these circumstances, going 6-5 and +17 in the third does not represent progress, but actually slight regress.
So, what are reasonable expectations for Coach Weis? If in the first year, ND is around +100 that should be taken as a very good sign. Holtz took over a team that was -4 and then went +86 his first year. A 90-point improvement for next year would have ND at +107. If he follows the path of Ara, Devine and Holtz, years two and three will build from that level.
Nobody reasonably expects a national championship next year. Nobody reasonably expected one this year. But Irish fans were right in their assessment that this year's performance by coach Willingham was a fatal blow to the notion that he'd ever be able to produce consistently strong teams at Notre Dame.