Part of the problem of any trade deal is that you'll end up pissing off one group at home to make another one more happy. Trade negotiators argue they need to have the deals be negotiated in secret or special interest groups will cause too much noise and trade deals will never get done.
The legislators are forcing this pact specifically because it promotes certain interests of various corporations. The group that will end up getting pissed off is the public at large when their quality of living is reduced. Novartis et al will get their rapacious drug profiteering enforced onto countries that currently aren't under their dominion, and the people who live in those countries will suffer through high prices for medicine because their politicians got a fat kickback.
Special interest groups are driving this entire partnership from start to finish.
It's true of business deals too. Typically the managers will negotiate the deal in private, and then present it their board and/or shareholders to be ratified.
It's just really hard to make significant decisions in a large group of people. Anyone who has been in a huge meeting, or on a big committee, will understand that.
If you try to give up one thing (e.g. free trade) in exchange for another (anti-counterfeiting provisions) and you get jumped on as soon as you suggest the first you never get a chance to broach the second.
Maybe the solution is to have a mandatory waiting period after the full text is released. 90 days before any votes can take place, something like that. Gives people time to go through and actually evaluate the proposal as a whole.
And the ability to rubber stamp a 6,000 page monolithic treaty which has already been agreed to is a complete joke. It's about as democratic as a parent asking a child, "would you like to go to boarding school or boot camp?" The democracy happened during the negotiations and amendments -- at that point the needs of each constituent were considered, included or excluded, compromised. Unfortunately the citizens of these countries or their elected representatives or anyone willing to represent their interests weren't invited to that party.
The negotiation would be harder, sure if it were public but that's because making an agreement that is fair is a lot harder than asking corporate lobbyists to narrate a wishlist and typing it up. All they had to do was reconcile the many, many different wishlists (still very hard), not put forth an agreement that actual citizens would approve of (much harder but what they should actually be doing).
[1] http://www.vox.com/2015/10/26/9619214/budget-deal-congress