The OP isn't asking if the bike will be suitable for loaded touring; he's asking if it will be suitable for light touring. Now, before we proceed any further, we should make sure he means "light touring" and not "loaded touring." If he's using it for light touring, he won't be carrying the panniers front and rear that are part and parcel of loaded touring. He might be carrying a bag or two, but not much-- just enough to carry some food, water, clothing, and a credit card.
So, if he's not carrying lots of bags, he's looking for a light tourer. If he's planning on carrying lots of bags, he's looking for a loaded tourer.
The Grand Prix would not be suitable for loaded touring. It would be suitable for light touring, although it's no the best choice out there-- mainly because of the weight of the bike and the steel wheels. Other than those drawbacks, it's a sport touring bike, and therefore the geometry will be relaxed enough for touring.
I'd say the main change you would want to address are the wheels-- get come alloy wheels. The gearing will be fine for light touring. You're not going to get lower than that 34 in the rear, so if you want lower gearing, you can convert to a triple crankset.
If you're getting rid of the foam on the bar, you might want to also change the brake levers to aero levers for an extra riding position. Even better would be aero levers plus 'cross-style interrupter levers (unless you're riding with a bar-mounted front bag), and bar end shifters. Add a rack to the rear, maybe some fenders if you're going to be riding on wet roads, and you're good to go.