I don't see how this is an over-reaction; a higher tier of an old raid isn't all that new. The legitimately 'new' content is a measly five bosses, for which they have been preparing for (minimum) six months. That is insufficient in terms of providing end-game content to those for whom its consumption is a priority. It is a fair statement, and a valid opinion, to express discontent at how paltry this latest offering is.
Although I agree it's a very long time. Much time in general has been sidetracked to work on first the Transfers which were clearly not part of their original plan. And now F2P transition as well as the entire restructuring of the studio.
If they can release a 5 boss Operation every 4 months I'd be happy. If it was every 3 months that would be amazing, but I'm not gonna get my expectations too high up despite their claims of faster content.