Things have changed a bit since our last two discussions on this subject.
We still need platform tags for when issues are platform-specific. This is pretty important at times, and there's always the non-game-specific questions about a platform.
We have tag wikis now, so this makes a great place to note the information on consoles. It will not affect the tags on questions, but it gives us a place to store the general platform data for a game when it isn't relevant to the question.
There are now tag sets. While a community-maintained set of tag sets for each platform would be even more ambitious than my previous proposition, it's always a thought. Unfortunately, there's no way to use those for ignoring tags, or directly integrate it with the site of your choice. But perhaps a creative mind can put some of this logic to use.
The strongest benefit of console tags is in tag favorites and tag subscriptions, allowing users to filter information either by what consoles they own or what they do not. Which is a noble endeavor, but ultimately infeasible due to the breadth of platforms and the 5 tag limit. The tag limit, as well as the character limit on tags, is pretty much set in stone. In essence, we are using a very limitted tool to accomplish this filtering. And as time has passed, I feel that our resources in this regard are terribly insufficient and inaccurate, due to the many months of people deciding rather haphazardly whether or not to use a platform tag.
When it comes to questions that are not platform exclusive, it is a very vast amount on both tagged and untagged that trying to enforce either one without consensus is dangerous. Yes, we currently don't have a consensus, but that's because our ideal scenario is the aforementioned noble endeavor, and to a very weak effect it is getting used in that fashion currently. So it actually has been working fine to take this rather... "relaxed" position on this issue for now. Until we either come up with a better solution to allow this filtering, or until we definitively decide to abandon this system outside of platform exclusivity.
Whichever side of the fence you fall on, please don't try to undo or do the status of existing, old questions. The volume is too much to have any impact and the most that will really occur is that mixed signals will be sent. Lots of "Do I or do I not?" Meta questions will not help whilst we do not have a proper answer.