As far as I know it is pretty complete, after all it has the images from the index books.
If the deceased person left a will, then there will be an entryin the index as Probate will havebeen granted to enable the executors to carry out their duties.
If the deceased didnt leave a will, then someone may apply for Letters of Administration to enable them to deal with the deceaseds estate, and if this is the case there will also be an index entry. However, this was not always needed - sometimnes a bank or suchlike would require it before releasing funds, but many of our ancestors never had bank accounts - their "estate" was probably just a few clothes, maybe a couple of chickens and if they had money it was probably tucked under the mattress! So there would be no need for Letters of Admin, and thus no record.