You have had a disc herniation at L5-S1 for a year now. Your symptoms are of no leg pain but continuing numbness of your right thigh and numbness of your foot, only when walking. You do have lower back pain from 4-6 on a VAS (visual analog scale). You note your “right leg is deteriorating” and later note weakness of the calf muscle.
This sound like a classic case of an S1 compression radiculopathy. S1 is the nerve that becomes compressed with a disc herniation at the L5-S1 level. It is disturbing to hear of weakness one year out from the disc herniation. I am not sure that the muscle will recover even with surgery but I do agree with your surgeon that surgery sounds indicated. The best chance for motor strength recovery is with a decompression.
Since it has been one year since the herniation, consideration of a new MRI is warranted to determine the extent of compression and to look for bone spur formation. I am also somewhat concerned about your lower back pain. Is the pain central (in the center of your back) or is it off to the side? If the pain is central, it may not respond to a microdiscectomy but that remains to be seen.