Greater blink | EN World Tabletop RPG News & Reviews

The 5th spell greater blink from the Spell Compendium is pretty powerful; it works like blink, except that the caster controls perfectly its travel from one plane to the other and can freely appear in the material plane just long enough to attack and then retreat back to the ethereal plane. I would like some help in finding ways to counter it (from a DM's perspective).

I know that a NPC with see invisibility can see the ethereal PC, but then only force effects can affect him. Spells that provide etherealness are at higher levels and so not generaly available. A ready action allows a caster or range attacker that can see the ethereal PC to strike the PC when he appears, but I am not sure it is legal if the attacker cannot see the ethereal PC, since the text specifies that the PC attacks as if invisble (removes the dex bonus from his target). But what to do when the NPCs or monsters are melee combatants and cannot see invisible PCs? I am pretty clueless as to what they can do...