I don't get why the offense will necessarily be worse. It should be better than the 2007 offense by the end of the season.
All offenses that Paul Johnson has taken over have improved immediately except for GSU in 1985 which was his first year as an OC. Here's the improvement in scoring offense in his first two years during Paul Johnson's career as OC/HC:
GSU 1985: -0.4*
GSU 1986: + 10.5 (+10.1 in 2 seasons)
Hawaii 1987: +8.3
Hawaii 1988: +3.9 (+12.2 in 2 seasons)
Navy 1995: +3.2
Navy 1996: +12.4 (+15.6 in 2 seasons)
GSU 1997**: +9.4
GSU 1998: +11.1 (+20.5 in 2 seasons)
Navy 2002: +5.9 PPG, +50.1 YPG
Navy 2003: +6.3 PPG, +54.1 YPG (+12.2, +104.2 YPG in 2 seasons)
* GSU improved through the season and won national title while avging 37.6 PPG in last 7 games including four playoff games.
** I also compared to the offense of Stowers' 9-4 95 team and the numbers were about the same. Ellwood's 96 interim offense actually improved a half point per game.
It's true that these teams were all option teams when Johnson took over. But at least two of them, the two Navy teams, were really, really bad at it.
Now 2009 should be very interesting, especially if we do better than most expect in 2008. Paul Johnson's second and third year results have been pretty stellar:
GSU 1986: won second consecutive national title, undefeated in 1AA.
Hawaii 1988: 9-3, beat Iowa and Oregon, only 2nd 9-win season since moving to D1 in 1974.
Hawaii 1989: 9-3-1, beat 10-3 BYU 56-14, breakthrough win was first Hawaii victory over BYU after joining WAC in 1978.
Navy 1996: 9-3 and a bowl win, tied with 1978 for best record since Staubach in 1963.
GSU 1998: 14-1, lost national title game.
GSU 1999: 13-2, won national title.
Navy 2003: 8-5, won CiC trophy for first time in 22 years.
Navy 2004: 10-2, most wins in USNA history, first back to back CiC trophy for Navy since 1979.