Plant's vs. Zombies 2 had a major reworking. They removed all of the locked games completely and made all the levels purely linear. They got rid of the concept of redoing levels with challenges to earn stars. They replaced both of these with nothing at all.
Now I'm not exactly sure what motivated them to do this other than possibly the game doing poorly, though I can't find any indication that it actually did poorly. Rather it is winning game of the year awards and was downloaded 25 million times in the first month after its release. But when several months after release a game has a major redesign that removes elements of the game and that does not unlock a fourth level that has been sitting locked since the game came out, it makes you think something must have gone wrong. The thing about free to play is that you have no idea what 25 million downloads means in terms of dollars.
But if your game is doing poorly then removing the majority of your monetization from it doesn't seem like a way to fix that. Sure, lowering prices might help, but simply taking out the parts of the game that you hoped people would pay for... well, I don't quite get how that increases your sales.
It's possible that making the game linear without all the unlocks is more appealing to a certain segment of players and they hope that this segment of players will buy the extra plants and the boosts that they weren't buying previously. Maybe the reason people weren't buying boosts and plants was because the game was tedious and they didn't want to play it.
But the idea of getting these people back into the game by taking out the stuff in the game seems dubious to me. I would think that people who do things like buy the extra plants would tend to do so during the honeymoon period and not during the part where they are bored with the game.
Anyway, I really don't understand the redesign. Of course I don't understand the original design either, which, as I have said before, seems like a feature-light copy of the first game that wants you to pay more the less you want to play. Now it is a feature-lighter version of the original. I sure wish they had simply added a couple of features and a bunch of levels to the original and asked me for $20 for it, and then they'd have my $20. But in this new world of free to play games, it is pretty clear that almost no one actually wants <i>my</i> money.