And that's way changings in basics of Nxt shouldn't be globally voted by coins.
There is no other way.
Another way: Voting power by some logarithm of fraction owned of all coins, weighted by account age. The latter discourages endless scattering of NXT to circumvent the logarithm (which would be a real problem in a naked log system).
Smaller, but older accounts could be on par with new big accounts in that system.
Ur way looks vulnerable to Sybil attack.
If the weighting/decay is strong enough, and unless he doesn't split his moneys into several accounts with the same amount of NXT
right now or somehow very early, he will not be able to do a full Sybil.
Add: The more a big stakeholder shuffles his moneys around to ever more new accounts, the less voting power he will get, due to temporal decay.