Good riddance about Pursuit -- that move was always uncompetitive and unfair and it needed to go.
It combines the worst aspects of the most controversial move in the game, Stealth Rock, namely its type-discriminating potency, and Arena Trap/Shadow Tag, the quintessential uncompetitive abilities.
It's been flying under the radar for years because of its limited distribution (that incidentally coincided with many Smogon favorites such as TTar, but I digress) and caused too many "dead if you stay in, dead if you switch out" scenarios because Ghost and Psychic types aren't exactly known for their physical bulk.
It might be shocking news now but we'll get over it. The metagame will be better without this cheat move.