Gentle curves can be stitched with your walking foot. Using a template....do you mean the 1/4 inch rulers used for long arming? I have a couple of extra thick straight edge rulers that I use with my regular machine when FMQing. I use them with my Machingers gloves on so I can get a good grip. I have part of my hand on the ruler and part on the quilt to guide it when stitching.
Unless I am stitching straight lines along my sashing with my walking foot, I tend to use my FMQ foot for most of my machine quilting. If you use the FMQ foot you can stitch in any direction which makes handling a quilt though the machine harp easier.