In the Rules Questions subforum, there was recently another question about the interaction of Ironworks / Trader. I noticed that you didn't say anything specific about this confusion in your Dominion Time Machine post a while back (http://forum.dominionstrategy.com/index.php?topic=3353.0), although you did say you would consider dropping the reaction on Trader.
If you had it to do again, would you reword Ironworks somehow? Which (if any) other cards would you reword purely to clarify intended behavior / interactions?
I don't imagine there's a better wording for Ironworks that isn't just confusing for no benefit. Trader issues are most easily solved by not doing the reaction part of Trader; the game doesn't need any particular card. If I wanted to do the reaction but somehow simplify it, it could give you a Silver in addition to whatever (non-Silver) else rather than instead of it. The main argument against Trader as it stands is that the game has only a tiny number of "replacements" (things that happen instead of other things), and so they are especially confusing; it would be better to do none at all or to have them be common. The reason I considered dropping the reaction in that post wasn't rules issues though, it was just, I had wanted the set to be simple enough to be a standalone and dropping that reaction is a step in that direction. The top was a compelling card by itself and it's so much simpler not to have a reaction too, even if the reaction is simple.
In general for any rules question the issue is, how much does this come up. Sometimes it's never coming up except for people who want to poke at the rules; those things are not much of a problem. Sometimes it comes up but very rarely. Sometimes it comes up but if people get it wrong it's probably not so bad; the key thing is that people can come to an agreement by looking at the rulebook. So in general what I care about is failing to include a particular interaction in the rulebook, rather than that particular interaction existing. If Trader's FAQ answered the Ironworks question then I would consider that sufficient there. I like common questions to be answered right on the card and well I work on the wordings.
I may have blown it on some random phrasings but I feel like I have already looked through the cards for these things, in particular for that post you cite. Where earlier cards don't match later ones, I would probably switch to the later style, such as saying "Silver" rather than "Silver card."