No, its flat. A flat tax is not progressive. The point of a progressive tax system is that the marginal impact is greater at higher income levels.
> Increased income has no tax disincentives (your tax rate doesn't change because you move into a higher income.)
In a progressive income tax system where the top marginal rate is <100%, there is always a positive incentive to higher income (well, so long as the marginal utility of additional income is non-zero; there's considerable evidence that for most people, there is some level where this assumption doesn't hold, but that isn't a tax disincentive, and tax rates don't really have any effect on it, since they are a multiplicative rather than additive effect on utility, they never take a nonzero utility to zero.)
> Simplifies that tax code dramatically (which would also increase revenue.)
Only if the flat rate is set very high compared to the existing rates paid by most of the population.
> 4) Doesn't artificially encourage capital gains manipulation by large income holders.
If this includes taxing capital gains as income, then this is true, though many flat tax proposals I've seen haven't taken that step. I'd agree that that choice is desirable independently any other changes (and it really has nothing to do with flat vs. progressive taxes or basic income.)
> 5) Removes government manipulation of social policy by giving them ONLY two number to play with... MBI and tax rate!
To do this, government has to alter the definition of taxable income (as well as many other things.) This does not eliminate their ability to make similar decisions in the future, so it doesn't remove any levers. (And, of course, government intervenes in social policy through things other than direct benefit programs and tax policy, so even fixing those wouldn't have the effect described here.)
Generally, I find "autopilot" arguments of the form "once we get government to decide X, government won't be able to decide other things incompatible with X in the future" to be ludicrous.
> 6) Finally, it provides a real mechanism for everybody to feel the effects of tax rate changes.
I'm not sure this makes any sense. Everybody feels the effect of rate changes now, but the utility effect of rate changes is different depending on circumstances. In a flat tax system with MBI, the same thing is true.
> ALL of these effects without negatively affecting market freedom.
Define "market freedom".