Batfink to be honest i don't see how anyone can say that development is Nth % complete anyways.
in my experience when you develop a game or software title you have yourselves a todo list of sorts; or rather a rough outline of what should be in it, plus story and such.
Although the engine could have say 10 features, technically thos features can expand and contract at any time for any reason. Perhaps a new technique allows you to make your shadows from hard to soft, or maybe new networking allows you to expand your users and data carried between them.
Even so that 10% complete would only mean you've finished 1 feature, which again usually isn't true because most people go back an edit features so they can get them working with other features.
(you can't paste together 10 tech demos and expect them to work out of the box, it does take time and effort to achieve them all at once).
I think when people say how much of the game is done they should really speak more on how far in to development they are.
Rather than saying - well we have 10% of the engine complete, they should say. well we have a working engine which currently has such'n'such features.
Sam (Everwhat) 's post on deathbed really is more of how things should be presented to the community. Although yes everyone works differently, there isn't really anyways to say how much is honestly completed in clean percentages and such.
Anything could change at anytime.
