I think they turned out for the better in the PZ campaign.
The Doomsayer would´ve been an absolute pain as a 4-target ET, especially in such a claustrophobic map as Bangkok…
Patient Zero just seems way too restrictive given how it requires you to wear a hazmat suit and kill Cage with a lethal injection. The current version allows for more freedom and we get the bonus of having a 100+ target mission lol 
The Author seems like the most classic kind of ET, and is particularly interesting due to being set in the Landslide version in Sapienza. The idea that Black is a fake is also pretty neat (I don´t believe there´s anything about that in the final mission?) and would be interesting if there was any special dialogue in that regard. Nevertheless, I prefer the current version with the horror-like vibe.
The Conditioner is perhaps the one that´s lost the most, and I´d be interested in hearing what dialogue Paine had in that mission. However, I´m not really fond of Colorado ETs, and just like The Doomsayer, this one would´ve been a pain (pun… not intended) with the additional targets. As a regular mission/Special Assignment though, I would´ve liked the concept, particularly if it had the daytime setting of The Vector.
And of course we get to enjoy the PZ missions during unique times of the day.
Indeed, the concept is pretty cool and would´ve definitely worked better as a SA/regular mission, but I´m still not sure I would´ve liked to have 4 targets in Bangkok, especially since I imagine they would all be concetrated in the same two-floor apartment area…
The Colorado concept is a bit more intriguing. We did basically get it in a sniper assassin form, but still could´ve been nice to get to roam sunny day Colorado… (then again, I tend to criticise the main mission for not doing enough to justify its 4 targets, so…
)
I´m actually one of those people who wouldn´t mind paying for permanently playable ETs (all of them) as a DLC. I certainly would mind less paying for them than the 7DS, so… 
Indeed. Still hoping for those Caruso brothers 