saw recipe to steam vegetables using a home made broth instead of water, opinons on whether steaming veg over broth wil enhance flavor.

If the veg isn't touching the water, I don't think it'll make a difference what liquid you use to steam.

If you're multitasking, like cooking rice in broth, or heating broth for risotto, then go for it. But I'd just as well steam veggies over water.

Yes, it does make a difference. Classic cuisine often cooks veggies in a "court bullion," which is a fancy name for seasoned water. Veggie stock with herbs, salt and pepper will infuse flavor into your vegetables, meat or fish as it steams. The flavor will be subtle, but there :-)