Actually could have a (totally unintended) positive effect in putting transaction cost into arbitrage, day traders, and program trading, it would seem to have a pretty tiny effect on actual value investors.
The volume on which they are basing their revenue projections will of course dry up, just like large boat sales did under Clinton's luxury tax on yachts, so instead of producing a lot of tax revenue it just puts the brakes on the velocity of transactions, hard.