Houston are not the better hitting team:
Stl 1st in NL 855 runs 214 HR .804 OPS
Hou 6th in NL 803 187 .778
In the bullpen :
Stl 1st in MLB 31-16 1.13 WHIP .225 BA 3.01 era
Hou 16th 27-24 1.34 .254 4.10
And as far as Starters go, Houston just burned out their best two.
St.Louis has the homefield advantage, and even if they didn't, their road record(52-29) is better than Houston's home record(48-33)
Of course none of this means that St.Louis is going to win, but they do have the better hitting and better bullpen, not Houston, as you said.