It might indeed not promote World PVP, let's hope they have a fix for that. More changes and a blog on the current changes should be here soon.
Judging from the twitter, they are aware of the impact this will have on WPvP, at least on the level that it will be more desireable for WPvP players to PvE for their gear than PvE. But Blizzards stance on it appears to be:
1) The damage to WPvP is worth encouraging PvE players to engage in PvP. Presumably the main reason for this change is to get more players doing both PvP and PvE - so PvErs do not feel excluded from PvP.
Whether PvPers are excluded from PvE is debateable - I think that with the exception of LFR, which is kinda like Random BGs, they are, since boss fights essentially become a DPS race and PvP power/resil is useless.
2) Massive WPvP fights are no longer viable due to realm populations being unbalanced. They most likely intend to shift the importance of WPvP into instanced PvP, and promote the latter at the cost of the former.
Of course, everyone does what they enjoy, so I understand that it doesn't concern those players who are not into WPvP, hoewever WPvP is far from dead on several servers, and still has large active communities, and I think these changes are not beneficial for them.