I think that FFG MUST announce the list of the monsters that will be recast
FFG owes you nothing and MUST do only what they think is in their best interest as a financially responsible company. There's a very real chance that these monster/hero packs won't sell, or that costs might spike for some reason, making them prohibitively expensive. At that point, any "plans" they announced will be interpreted as a promise and they'll be seen as breaking that. It also gives them the flexibility to do what works and scrap or change what doesn't. This is why they don't announce anything until they are well into production with it and have almost everything hammered out. (You'll see the same behavior across the entire spectrum of the gaming industry)
Nor do you owe them anything. If you don't like their practices, you don't have to support them. You've already got a lot of their stuff, and them producing new material isn't going to affect you other than your own psychology telling you that you should be upset for some reason.
They will balance the desires of their clients (us) with the market as a whole. They pay attention to market desires and also know (unlike many people on these and other forums) that those on various forums are a very small (albeit passionate) percentage of their buyers. They may be the most likely to buy everything, but my guess is that all of the money they get from everyone who commits to buying everything is still significantly less than all the money they get from everyone else who only buys a few things here and there.
Feel free to suggest what you'd like to see, and if enough people do so, (or if they think you have a well-reasoned, and respectful point), they may choose to do so. But thinking, and worse, acting, like FFG has some kind of obligation to you, or that they MUST do something for your benefit (or that of some small sector of other people like you) is naive and petulant.
Remember that they originally said that they had "no plans" to release any of the 1st edition stuff (but they didn't say they wouldn't ever, at least not in any official capacity that I can remember). This was probably because they felt like there were enough people with 1st edition out there that it wouldn't sell. (The reason most businesses don't plan on doing something is because they think it won't make them much money.) Eventually, I think they realized that 1st edition stuff was being sought out by A LOT more 2nd edition players than they initially expected, and realized that that there was a hole in the market that they could fill. But instead of just doing so in a way that didn't improve anything, they are giving people a reason to go straight to them instead of tracking down someone else by improving the sculpts, bringing the artwork into line with the new edition, and supplying new quests.
Personally, I'm glad to see it. I may never end up buying them (though I probably will eventually), but it's a sign that there's life in the franchise.
TL;DR: Plans change, deal with it. Stop acting like you control the company just because you've bought a bunch of their stuff before.