So, a few things:
A) This change means Wardens will draw Physical and Tactical Mastery from Agility, not from Might.
B) The change was announced on Twitter, yes. It is not the only place it will be mentioned.
C) The reasons for this change are because we feel the Warden is better suited as an Agility class -- it is the tank which functions by avoiding attacks, not by standing there and taking them. It also makes itemization in general take substantially less work to have one primary stat for each armor type.
D) We recognize this is a rather massive change to introduce in the middle of an expansion. It is being done now to coincide with all the additional gear which will be introduced with Update 10 (also announced via Twitter).
E) The "grace period" mentioned will be a period of time where Wardens draw Physical/Tactical Mastery from BOTH Agility and Might. We recognize to completely switch streams without any sort of extended period of time would leave the class in an un-playable position.
F) The Hytbold sets will be converted to use Agility as the primary stat.
G) Pieces of jewelry which have only Vitality or Agi/Vitality as their primary stats will appear more often.
Link to the Twitter Dev Chat transcript:
http://forums.lotro.com/showthread.p...16#post6635616