I just wanted to post an observation mentioned by another designer (Swiftshadow). He was talking specifically about playtesting and how people offer up ideas after playtests. Oddly enough I feel the same way like he does: some ideas sound good (especially the very general ones) but turn out to be terrible in practice.
I know sometime a designer mentions worries about being copied or having an idea stolen by some one else... And I find that reality to be so impossible because many ideas or concepts surrounding a game simply can be used in other contexts... Even with mechanics, if I say "I am using a Deck-Building Mechanic" this is a very broad and general statement. There are many such games which are each using the mechanic in some form of creative way unlike the other games in the market.
So where does this all lead? Well that basically ideas are great - but don't always work in a game... This is especially true with the more general ideas.
This was just an observation, after having designed the 6th version of my current game.
An example would be the statement similar to "I would use dice just to make things a little more random" (I am paraphrasing of course...)
Another example would be a designer explaining how he would have 4 stats around a card, a players could choose to select the stats by turning the cards to the desired stat. When I read this mechanic, I was curious... Sounded like the idea would be worth exploring. And so I did just that, I built up a deck... And found that in reality the mechanic wasn't good at all in practice. Basically the number of possibilities were 4 but you also had to remember that you did not want to duplicate a stat and so therefore any stat implied another card needed to also be turned. Ultimately not a good mechanic at all.