Marketing_Guy - 10:25 am on Feb 29, 2012 (gmt 0)
Well, we're not talking about depreciating a 301 entirely - just it's ability to act as a signal to determine what the topic of the target page is.
The assumption would be that 99% of website owners will be smart enough to maintain the same content / similar site structure with their new site (either same domain with different URL structure or new domain entirely).
All Google needs to do is pass a top level PR value to the homepage of a domain (can even be based on total IBLs, even to deep pages) and let the site's internal structure dictate how it is distributed throughout the site. 301's don't need to play a part in that process.
At some point within the site move process (which takes months via WMT), Google runs a process that matches old page to new same page internally (same mechanism that detects dup content) and could attribute deep link PR, etc that way.
Just thinking out loud here, but it seems to me that webmaster driven 301's were an easy, low resource way for Google to manage this process, but flawed because it can be misused. The question now is Google's technology / ability / processing power sufficient to do a better job internally?
Purely from a search point of view, what value is there in relying on a 301 that I (the webmaster) can control? Is it always used appropriately? Can it be misused? What's the margin for error there? Can I achieve a similar or better effect internally?
Just speculation of course. :)