As for tweaking the "power" of upvotes, I think this would probably have unintended consequences. Like creating an old boys' club perhaps.
Step one: Make new account
Step two: Post Techcrunch or similar article guaranteed to hit the front page of HN.
Step three: Use newfound insane karma average to upvote crap submissions.
Step four: ???
Step five: Profit.
I actually like "Remove submission karma.". That should stop the linkbait articles from people who have to have their play money.
* Have a karma cap for submissions. It could, for example, only give one karma for every ten upvotes (rounded down to discourage people from posting many articles). There could also be a hard maximum.
* Reward less karma if more people submitted the link manually. This gives less karma for popular things such as Paul Graham essays, TechCrunch articles, etc. When other people submit an article, it should still reward the article itself with upvotes, but it would make sense to reward the poster less since it is likely the story would have been posted anyway.
These alternatives are better than removing submission karma in that they still reward people for posting interesting content, but are worse in that they make things a little more complicated.
I like the suggestion I saw weeks ago of just ditching submission karma. When people have no incentive to automatically or manually dump everything Ars/TC/etc publish then the quality of stories might go up.
Edit: found the suggestion, it was by Cletus:
http://news.ycombinator.com/item?id=3788875