Yeah its a fair point. Personally I don't like having locked in trade outs as too much can change (teams, weather, etc), so having the ability to pivot is useful. Always good to have a plan, but what are the consequences if it doesn't work out. I would also question if using a trade this round for a 1 game score is worth it given the variability of big bash scoring. A lot of people were thinking similar with Doggett the week before his bye and he scored 5..
I guess it depends a lot whether you are just trading Round by Round or looking ahead as well.
Sometimes it can be hard to even find players to trade out each round especially if they are of benefit in upcoming rounds.
With the introduction of the Flex our thinking has quickly changed , maybe it is more beneficial some rounds just to get 11 to play and hold onto a player.