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.
It's not a rehash if it is truly all new mechanics are they previously advertised.