Progress bar isn't so great idea imo.
For example: the progress bar is on 80%. What if they wanted to rewrite all of the code, even if it would took months, because of some nasty bugs?
The progress bar should drop on 0% ? If that happened, many ppl would start whining on forums, complaining etc.
And another example: the progress bar is on 20%. They've did a lot of work, and it raised to 75%, but suddenly, they found a bug somewhere, so it dropped to 55%. They've managed to fix it, so bar went up by 5%, and its on 60%, even if its the same as it was in 75%, but with fixed bugs. And ppl would whine and complain as well, like 'OMG WHY THE PROGRESS BAR HAS BEEN LOWERED?!?!?! !!!11one1eleven'.
And again, its hard to say how much % is completed. So posting on the blog would give the people possibility to see, what have been done, and what's being currently worked on.
You see that now?