"metal ranks reset weekly"-phenteo

Does this mean that we only have weekly rankings? Even though games last around 9 mins, I don't see how our skill could be calculated correctly over just the course of a week so that we can play against somewhat equal opponents.

Not everyone plays multiple games weekly. At the same time, people hardcore enough to play the game all week so that their skill is calculated correctly (and they face equalish opponents) are probably hardcore enough to want a permanent ranking or at least a monthly ranking. And even a casual play may be disgruntled to find that he or she end up against highly rated players because he/she plays only once a week!

The game looks amazing and I've been following the fireside gameplay but solely weekly rankings seems too casual and bizarre for me personally, what do you guys think/ is this true?

I think blizzard has a knack for making great games but also ruining great games by poor design choices made to manipulate game competitiveness so I have some fear...Its already a turnoff that there is no chat system in the game -- I hope we can meet players on the Bnet interface, but I guess this is another issue for another time ;)