Game will be dead in just over a year, based on the current number of Rookie dots, how many of them will be retired on their way up, and the small number that will be left once they're old enough to play in WL and National Pro. WL and Natty Pro owners at that point won't have enough new and upcoming dots available to replace the older retiring and declining dots, and that will be it for this once-awesome community.
So, no, don't buy Flex. You won't get nearly the same value out of it now that you would've gotten in the past.