Nice observations - I was thinking Iglesias before Farmer. With Farmer he is not needed and we could get another Right handed OF, but your observations are right on. I want value throughout the contract not 4 good years and then an oversized payment to someone taking up roster space.
The average age of decline for a SS is 33, it is the time Correa might be expected to shift over to 2B. Correa could beat my 4 great years and decline message, but the fact he does not have the speed of a Turner works against longevity. However my statement applies over all the signings - not limited to Correa.