A ranger with favored enemy goblins and giants will outshine almost any other melee you bring to the table with the exception of a barbarian - and if they focus on archery they'll outdo the barb in many encounters.
In my game (mid way through book 3) our ranger makes the wizard look like a chump - the ranger is a 100% unoptimized and the wizard is a vet that plans things out.
Heck the ranger did this with a single magic item up to book 3.
I think you vastly are underestimating what a ranger can do. I hope your wizard has use magic device to backup the bard. The ranger can use divine wands and scrolls fyi without a check - so really you all need to back each other up with that stuff.
I'll admit - I think if you try to 'push' someone into a role they don't want - it just makes the game unfun for them - so I'm biased on your actions here - if you feel the party needs a different role why don't you provide it? I will say the AP can be done without a wizard.