Isn't it precisely what is implemented in Monero? (except you don't have a rollover pool, the penalty is simply deducted from the block reward for good).
No idea what happens in Monero, but if so, more power to them.
In theory you could have the penalty coins vanish here as well, but that has several disadvantages.
So, I support the idea. Just that 2T is a bit high, will that work? I mean, will it be possible to download a blockchain with 2T blocks in it? A 2T blockchain consisting of smaller blocks is not an issue, but what happens if the download gets stuck DURING the 2T?
Is the Bitcoin client ready to download blocks partially and continue after a crash/shutdown/process kill?

In case it's unclear, T doesn't mean terabyte. It's just a parameter that can be configured based on our needs. At this point in time I suggest T = 3MB.