That would be desirable. Given the direction that all government pensions seem to be taking, getting ones' earned assets out of the hands of the crooked politicians and into the hands of the individuals is not a terribly bad idea.
That’s a good point. It would also put a cap on the amount the person gets from the Federal taxpayer. If ex-employees retained active Federal pension accounts, then future administrations could use the promise of higher benefits to buy their votes.