It depends on what you mean by "wedge".

Eg phalanxes could apparently use a "wedge" of 256 man units, rather than each unit being in a wedge. Ie each unit formed in it's normal square block, but flanking units were held back to give the whole army a wedge shape. I don't know of any case where it was actually used in battle.

Army-sized "wedges" were quite common - eg Vikings had a similar formation called a "pigs snout" with axemen in front, javelinmen behind and archers in the rear.

Individual units in wedge are well attested in a number of eras, and modern re-enactors have found they can indeed be very effective at bursting through lines, but they require some skill and considerable intestinal fortitude.

Cavalry wedges such as the Greeks used were NOT intended to aid combat - rather they were intended to aid manouvering - the soldier at each corner of the wedge or Rhomboid was an officer, and it was a simple matter to turn the whole unit so that a new officer was at the tip and leading the way. Traditional squares/oblongs had to shift officers around to get the same effect.

There is a lot of confusion about wedges in classical times because the latin term for wedge is "cuneus", which also means column, so most of the time when you read of a phalanx or other "wedge" it's probably a mis-translation and should read column.