Based upon the current rate of change, my speculation on how things might go for the year:
2010-12-07[-94] Cataclysm
2012-08-28[-04] MoP pre-expansion patch.
2012-09-25[00] Mists of Pandaria
2012-10-02[01] Arena Season 11 Starts
2012-10-09[02] LFR Mogu'shan Vaults - Part 1
2012-10-16[03] LFR Mogu'shan Vaults - Part 2
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2012-11-06[06] LFR Heart of Fear - Part 1
2012-11-13[07] LFR Heart of Fear - Part 2
2012-11-20[08] LFR Terrace of Endless Spring
2012-11-27[09] Content Patch 5.1 (+9 5.0)
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2013-03-05[23] Raid Patch 5.2/Arena Season 11 Ends (+14 5.1)
2013-03-12[24] LFR Throne of Thunder - Part 1/Arena Season 12
2013-03-19[25] LFR Throne of Thunder - Part 2
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2013-04-02[27] LFR Throne of Thunder - Part 3
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2013-04-16[29] LFR Throne of Thunder - Part 4
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2013-05-21[34] Content Patch 5.3 ?? (+11 5.2)
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2013-08-26[48] Raid Patch 5.4/Arena Season 12 Ends ?? (+14 5.3)
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2013-11-06[57] Pre-Expansion Patch - based upon current speed ?? (+11 5.4)
2013-11-08[57] BLIZZCON
2013-11-09[57] BLIZZCON
2013-12-10[62] Next Expansion - based upon current speed ??
-[What fills up these 12 weeks ?]-
2014-02-25[74] Pre-Expansion Patch - based upon 18 Month exp cycle ??
2014-03-25[78] Next Expansion - based upon 18 Month exp cycle ??