For the first, it's not ideal, but you could set a date range for the 'Top Logged Caches', which will effectively neutralise the advantage older caches have, of being available for longer. It would be a good stat to have though, I agree.
Not quite sure why you'd want the second one, as there's already the 'FP by %', which provides a very good indication of quality. In that respect, what is the difference between a ten year old cache with 2000 Finds (50% FP) and a two year old cache with 1500 Finds (50% FP)?