I have fished it for the last three years and agree the number of 20"+ fish is declining but they are still there just few and far between. What do you expect when word of the number and size of the fish gets out, lots of peeps bonking one. If it is truly to be a trophy lake and you want to get the mid and upper 20" fish back there should be a zero limit but that would have a lot of opposition now. I don't think there is any lack of food in the lake as the fish are very healthy, footballs.
I have said this before but the triploids are going to be insane as time goes by. I fish a lake with 3 year old trips and they are 23-24" and fight like crazy, your landing percentage is not very good.