Nintendo likes to make a game of everything, that's a key strength of the company. With Splatoon, our theory is that it's made a game of server stress testing, which perhaps explains the ongoing wait for the Ranked Battle mode - it was always expected, but is still slightly odd.
Earlier this weekend Nintendo of America tweeted an update on the Splatoon Ranked Splatometer, which supposedly shows the gradual progression of player numbers that will unlock the Ranked Mode - and its Splat Zone matches - when enough have reached level 10. An update from later in the weekend suggest that the unlock is now very close.
As we stated yesterday, this may be a genuine process to wait for enough level 10 players, or it could be an artificial way to limit online modes and manage servers carefully. This writer suspects the latter, as current matches are packed with players well beyond level 10.
In any case, based on this 'progress' we should have Ranked Battles soon enough.