<sup>There's a tldr; summary at the bottom for you skimmers, you know who you are...</sup>

There are two types of meta questions:

 1. Those that apply primarily to the
    specific site in question (such as
    whether a specific question should
    be closed)
 2. Those that apply to the
    stack overflow internet services,
    inc engine (such as bug reports,
    feature requests, etc)

Further, there are several levels of user engagement and abilities.  Once one has sufficient rep in any one community, they are given 100 rep in other communities, which gives them all the basics, except for downvoting.  It only takes another 25 rep (5 question upvotes, or 2.5 answer upvotes) to increase one's rep enough to get the ability to downvote.

If meta were solely hosting questions of type 1 above, then I'd have no objection to using some sort of calculation to allow advanced moderating equivalent to some function of the person's rep on stackoverflow.

However, I believe there is some value in treating meta.so as a separate community with a niche.  Yes, it services questions of type 1, but its community primarily serves and deals with questions of type 2.  In effect it is just as much a separate community as stackoverflow, serverfault, superuser, and the multitude of area51 spawned community sites.

In other words, it has a particular niche audience of experts who have worked with stackoverflow to some depth and for some period of time, not just as users, but as long-term contributors to the overall direction of the engine development.

For this reason, there is value in treating it as a separate community with its own, separate reputation system based on questions and answers contained inside meta - and not based on questions and answers dealt with in other sites.

The 100 rep bonus given just by having some experience with some other stack related site is enough to get most people most of the access they need.  The ability to downvote, tag, close, and delete questions should be earned, just as they should be earned if moving from stackoverflow with a 20k rep to a user interface site.

It doesn't take much community engagement to get that last bit of rep needed to downvote, and simply answering one or two questions a day on here will yield enough reputation to attain whatever level one wants.

I'm not convinced that having 20k reputation on, for instance, the electronics site should give one the ability to vote to close questions here, or even to downvote, without at least engaging with the existing meta community for a short period of time.  But it already gives the ability to ask questions, answer questions, comment, flag, upvote, and edit community wiki posts.

And as useful as voting, tagging, editing, closing, and deleting are, the best way to help move the community in any particular direction is using words - so the first and foremost feature, that of asking and answering questions, is always available.

tldr;
-----

It's a niche site, just like SO, SF, SU, etc.  While it's called "meta.so" the reality is that it is a community of experts (not just users, but experts and wallowers in the mud) in one niche, and the reputation system is and should be separate from the other sites, especially given that the 100 rep bonus for account association provides nearly everything one needs anyway.