Even if they weren't rested, those starters should eat SF for breakfast... and both Bullpens are pretty equal - neither being that impressive.
Verlander's starts account for what's basically an automatic 2 wins, if he even has to pitch twice in this series. Guy's a fucking nightmare to face, and gets even better once he gets over about 80 or 90 pitches. He's unreal. Once you think you have him figured out, and get a hit or two, he turns it up to 11 and his fastball begins clocking 101.
It's like he needs to pitch 70-80 pitches to get legitimately warmed up - and by then he's already K'd 5 or 6 guys. He then pitches 40-50 more 'ludicrous speed' fastballs, and strikes out the final 3 frames as if he's some sort of hybrid of Tom Glavine, Dennis Eckersly, and Randy Johnson.
Giants fans will be screaming at foul balls and popups, because the majority are going to be groundouts and K's.
and then Sanchez, Scherzer, and Fister are all staff Ace material in their own right, rested, and likely to go upwards 120 pitches if Leyland feels inclined to send them.
The Giants haven't faced anything like that. Neither STL, nor Cincy have pitchers even in the same dimension as Detroit. The only way to beat the Tigers so far this playoff is get a shutout from one of your own pitchers (Detroit's allowed the least shutouts this season in all of baseball), or knock out a starter and tee off on their average bullpen (especially Coke, who's like their only southpaw, and he's pretty shaky out there)
The only real weaknesses Detroit has are poor defense and an average bullpen. They make up for it with the best corner infield hitting duo in the league, crazy fast baserunners, and 4 baseball cannons.
If you want to say history, then maybe that could also be a weakness? Last time Detroit mowed down a team in 4 straight to get to the WS, they fell flat against an 83 win Cardinals team that decided not to suck all of a sudden once they won their pathetic division.