The way that your roof was done is the way that roofs have been done for at least a hundred years. The change from solid pine to plywood in the 1940's was supposed to be an improvement but they are still changing that with the recent addition of tongue and groove jointed edges. The aluminum drip edges seem to have started about 15-20 years ago. Their value seems to be mostly to support the edges of the shingles. With the changes in guttering, your future projects may be a bigger factor and the style and pitch of your roof may be a bigger consideration. In my opinion, anyway.