All of these would engender more criticism against Apple for policing their "walled garden" but is there a better way to solve it?
Typically the way that works is that someone diligently looks at every app and provides a rating based clear and transparent metrics. They do this in a largely unsung fashion as early adopters or randomly curious people begin to validate that their ratings correlate strongly with actual quality.
Then, once they reach critical mass, the app vendors will attempt to corrupt them (or at least influence them) by sending them 'free' apps or 'previews' which don't exactly match what they actually ship. Depending on whether or not this new effort has been around the block before they will either lose all credibility once they highly rate and app where the 'review copy' was significantly different than the 'store copy.' Or they have some other fail mechanism (like not actually reviewing the app instead trusting some third party's opinion)
If they dodge that bullet they will begin to grow in influence as more and more people will start using their ratings but that will also increase the demand rate ("Why haven't you rated app Donglefritz yet?") now it will switch from being something they were doing because they and their friends were tired of all the crappy apps and gaming the app store ratings, and it will start feeling like work because they are feeling pressure to get more and more apps rated. Also apps they rate poorly will start complaining, and some of them might try to intimidate them with legal proceedings (justified or not).
Suddenly the value equation will be all pear shaped, they will want to stop but too many people are counting on them. They will want to find some way to 'monetize' all this work since they are getting poor reviews at their day job (or no sleep) because of all the time they are spending rating iPhone/pad apps. They start taking advertisements and have to deal with how an app they rate poorly actually gets lots of downloads because the same app is advertised in their tool or on their site. The ad isn't an endorsement but they need to figure out how to explain that to their customers who previously only had messages coming from them that were not paid for.
Typically it is at this point where they 'sell' their brand, apologize and move on with their new found wealth swearing that 'next time' they won't cave in like that. Their new owners will milk the brand by turning it into a pay for play mouth piece for app vendors which will easily double their investment (since the brands legitimacy will die more slowly than the value of the rankings).
Once the brand is completely discredited and usage has dropped it will quietly fold and disappear never to be heard from again.
Oh, I'm sorry you wanted a solution? :-)
And if they're not doing it already, only publish reviews from accounts with a credit card.
As far as "this is crap, go build something better" - that's tough to say when developers show high (albeit juked via cross-promotion) download numbers, and is also difficult for developers to stomach without some kind of objective measure of what makes for a good app.
Benefits to third parties: They could host their own "app store" and monetize however they like
Benefits to developers: They could put their products in any store that will take them, or perhaps try for Apple's "high quality" store for potentially(?) higher gains.
Benefits to Apple: They could police all they want and people's claims of "Too much policing!" would be groundless since consumers can just switch stores, though it may be harder to monetize
Is this how Android works with Amazon's "app store" competing with the Android marketplace? How is that working out?
That said, the mechanic of different versions being rated independently is very important. Apps can go from great to broken or broken to great in any given update.
As a user, you can dodge a lot of the spammy stuff by focusing on paid apps.
I think this would solve most of the problems. It's clear this is a burgeoning market, and it's smacks of blackhat-SEO tactics (artificial rank improvement by deceit).