Internet Sales Tax wouldn't be bad if it were uniformly imposed country wide (what amazon has pushed for). This specific bill, on the other hand, sounds like a nightmare.
The only saving grace being that at least states would be required to provide "software" - I can only hope that translates to APIs - to calculate taxes. That would make the problem significantly more manageable but it would still drastically increase the complexity of billing solutions for a lot of SMBs. The million dollar threshold is just too low for this to be anything but crushing for small businesses.