Career stats for player are there (sweep through the player screens or select View in the bottom bar).
The problem with storing stats is indeed memory (or better: the lack of memory). But over time the devices will be much better (right now we try to support devices with just 128MB memory from which we only can use about 20-30 MB). Once we move on we have more opportunities. And we always try to find ways to include stuff even with the limits the hardware gives us.