Here's my vague (and potentially incorrect) memory of the sequence of events for the last few new Maiden studio releases -
Brave New World - artwork and song titles released a few months in advance, The Wicker Man video released maybe a few weeks prior, album out end of May.
Dance of Death - artwork and song titles (and writing credits I believe) released prior to the summer Give Me 'Ed Til I'm Dead tour. All fans think the cover is a fake and hideous. Wildest Dreams played on that tour followed by leaks of Rainmaker and Dance of Death a few weeks prior to release. Album out early September.
A Matter of Life and Death - artwork, song titles, writing credits all revealed in early June. Breeg single released early August. Different World and Brighter Than a Thousand Suns streamed on the site a few weeks later. A 3 minute snippet of the DVD that was to come with the album posted maybe 3 weeks before release. Album out end of August/early September
The Final Frontier - countdown on the site of the release of the new album details, again early June. Artwork, song titles, writing credits and El Dorado in mp3 form all released on that day (Maiden site laggy as all hell for like a week). The Final Frontier video released in mid to late July, album released in mid August.
I'm pretty certain about AMOLAD and TFF, the others are bit long enough ago where I'm hazy on those. Quite honestly, once the album is out (in 67 days) you'll forget most of the pre-release stuff anyway.
So, all this being said, I'm not surprised there hasn't been anything else official yet. If I were a betting man I'd bet maybe a single or video or something by end of July at the very earliest. Obviously we'll have magazine articles and whatnot before then to wet our appetites. My advice is to just try as hard as possible to be patient, it's a fun ride when there's news everyday.