Reasonably strong, however you will probably want to revise it to account for wood movement across the width of your oak leg. That 1x8 oak will account for a fair amount of expansion and contraction over time, and you have accounted for this in your top with the figure 8 fasteners, however for a structural leg as you show, you will have to get a little more creative.
You could probably route some horizontal slots in the stretcher at the end, and screw the leg into the stretcher through those slots. this way the top can expand and contract across the width, but will not move up or down against the table frame.