Community Wiki is the right approach, but the first thing we need to do is define just what a "valid" list question is.
As you mentioned, specific product recommendations are a poor fit. However, if we say "list questions are okay, but shopping questions aren't", many people are going to point out that this seems a rather arbitrary distinction.
"Too localized" certainly applies to most shopping questions, since available products, and even safety requirements, vary from location to location, and month to month. However, that is not the only problem with "list" questions.
"List" questions make it difficult to find the "right" answer, which is one of the main focuses of our platform.
They encourage people to post low quality answers (such as mentioning a title of a product that fits the list criteria, without providing an explanation as to why it fits the list criteria, or why the poster feels it is a good choice).
They discourage appropriate voting practices, as many users don't have interest in going back to vote on new answers 5, 10, or 20 times to the same question, just to check to see if the newest answers merit an upvote. Similarly, users who come to the question late are unlikely to go through all 20 answers and vote appropriately on all of them.
Community Wiki can help address some of these issues, but comes with its own set of issues.
CW breaks the reputation process. This was a conscious decision of the developers to deliberately discourage its use, but whether or not we decide to encourage or discourage CW, its something we cannot change. Questions that are CW get no reputation for the question or answers. Answers that are CW get no reputation. Reputation is a fairly important metric for most people, so bypassing the normal means of obtaining reputation is rather significant.
Most importantly, though, proper use of CW requires maintenance. Making the decision to convert to CW requires someone to go through and consolidate all the good answers, while eliminating any redundancies. After it is converted, users who aren't familiar with the concept are likely to simply treat it as any other question, posting a new answer, which someone else will then have to find, and incorporate into the CW answer.
All of this comes back to my belief that we should reserve CW for very special cases.
"Good list questions" can fall into that category of very special cases. However, as Torben mentioned in his answer here:
For one thing, we need to set a clear limit so this won't degrade into a catch-all basket that legalizes off-topic content.
So what are the criteria for a good CW question?
It must meet all other standards of quality for questions on our site. If it is off-topic, too localized, not constructive, etc., no amount of other positive traits justifies it being CW.
It needs to be of obvious use to a large number of people. Closely tied with not being too localized, it should be something where we can honestly expect a fair number of people to search for the question, hopefully driving more traffic to our site. "What are some effective tools for preventing a child from falling off of a balcony?" just isn't going to draw the type of hits we'd expect for our bedtime ritual question.
It should be a topic on which widespread agreement should be expected. There are quite a few controversial topics in parenting. The debate and general tendencies towards soap-boxing these issues can incite would make CW problematic. If it is reasonable to expect a significant number of people to disagree on general approach, it is not a good choice for CW. I.e. no CW questions or answers on circumcision, vaccination, gun safety, spanking, etc..
It shouldn't be a 'moving target'. If the answer will change over time, then it should not be Community Wiki. The simple reason for this is maintenance. Minor tweaks and revisions may be okay, but if it is reasonable to expect some fundamental "game changers" in the future, it is not worth making it CW.