I just posted a suggestion to Meta SE that questions that are non-specific to particular site-meas should be migrated to Meta SE. Here's the text I posted there:
On the various sites I participate in, I see many users asking technical questions about how SE itself works on the site-specific metas.
When these are purely about technical things that are the same for all SE sites, shouldn't they be migrated to this Meta SE? (They typically aren't. Just check out the "support" tag on any site-specific meta, and you'll a number of such questions, unmigrated.)
Now, certainly > 95% of these questions would be closed as duplicates here on Meta SE. So, I therefore recommend @Glorfindel's suggestion of closing questions on site-specific metas as duplicates of Meta SE questions (without migration.)
The same question can be asked 60 times on various site-specific metas. In these cases, the correct answers and input are the same for all sites. Some of them may go unanswered, some of them may have a low quality answer, some of them may not have votes on the answers, etc. Often, content is copied around. But when the source of the original post gets improved or updated (or a new, better answer comes along), it won't be applied to the copies. To avoid this fragmentation, there should be a policy that all technical questions that are the same for all sites should be migrated (or cross-duped) to this Meta SE.
That way, there will be high quality answers, plenty of votes, united resources, and no fragmentation.
If this is already a policy (is it?), It's currently not being practiced very well (as I explained above.)
If implemented, mods on all sites should be notified about such a policy, and encouraged to practice it. Maybe there could even be some system to make it easy for high-rep users to participate in such migration?
Of course, not all sites have to be forced to do this. If one community was to adamantly oppose it, they could of course have their way.
@ShadowWizard has made a very good point by pointing out that since many users may not know about Meta SE, they may thus miss out on useful questions if this was practiced. I agree with that. I therefore feel that this suggestion needs to be coupled with some feature to highlight the existence of Meta SE to users of various sites. I already know of a proposal on how to achieve that, but that's just one suggestion. It could be achieved in many ways.
If questions involve particular circumstances of a particular community at all, then they should not be touched as per this suggestion. A very liberal view of what constitutes "particular circumstances" can be taken.
Would Travel SE like to follow such a policy? In the support tag here on Travel Meta, I see a few questions that could have been migrated. I'm not saying we necessarily migrate all the past questions, but perhaps the future ones. For TSE Meta, there aren't that many anyway.