Almost certainly worse. As it stands, SEOs fear Google and the webspam team like they're the Wizard of Oz. You have a strong incentive to follow the letter and the spirit of the webmaster guidelines, because you don't know exactly what's going on behind the curtain. Once you start bending the rules, you're living in fear of being banned.

If the algorithm was completely transparent, it would give a home-field advantage to spammy SEOs, who could operate at the absolute limit of what is permissible. Legitimate sites that lack the resources to aggressively manipulate their SEO would be at a substantial disadvantage.

To give a real-world analogy, imagine a department store that decides not to prosecute shoplifters caught with less than $20 worth of stolen goods. If the rule is kept secret, then it's a perfectly reasonable tradeoff between security and the cost of enforcement. If the rule is publicly known, then shoplifters can spend all day stealing $19.99 products with total impunity.

Why would that matter? Do you think Stormfront are somehow at advantage when it comes to gaming unpublished algorithms?

Given the Santorum thing, nope...

I thought I knew what the Santorum thing being referenced here is, but maybe I'm wrong: how was Stormfront related in any way?

The question was, do Stormfront have an advantage here, and the answer I gave was, no, because left-wingers have previously successfully manipulated Google's algorithm to a much greater extent.

no one would understand the algorithm

We analyze and compare things that we don't understand all the time.