After initially voting in favor, I've decided to change my vote to a No.

Thanks to @azircon for discussing it with me, and to @jarvie for his clear and thoughtful comments below.

My decision to vote No is based on the following:

1. It's not fun: A "pay-for-chance" tax is not a compelling or fun game mechanic. Developing buildings on land = fun. Buying potions to get a higher chance of something != fun.
2. It's not the right priority: Though I agree getting DEC to peg is crucial, I'd rather the team prioritize building land development mechanics. These sinks will likely be much more than 10k DEC / plot. I'd want to see all efforts going towards that rather than on bandages.
3. It doesn't really benefit players: My assumption is that if everyone is a rational actor, then everyone would buy the land potions. If so, that's a lot of burned DEC, which theoretically is great for the economy but ultimately means nobody wins as far as their land is concerned (think of the extreme case: if every plot is rare, no plot is rare). Basically all that happens is DEC gets burned, but players are not really better off in terms of their land holdings. Again, instead of that, let's go faster towards actual land development, where players can make strategic decisions on what to develop in order to advance in the game.
4. It's divisive: This proposal is clearly quite divisive, and is upsetting players who have been in the game a long time. I think it's important to reward long-term supporters, rather than piss them off.
5. It sets a bad precedent: Although I initially found the land potion reasonable given the similarity to potions for card openings, the fact that this wasn't in the initial plan sets a bad precedent.