Legacy Alakazam (Psychic) vs Alakazam ( Future Sight)

Although Alakazam is only the third most powerful Psychic-Type Pokemon in terms of CP, it's arguably the best Psychic-Type attacker in the game. With an Attack stat of 271, Alakazam has the highest Attack stat of any Pokemon currently available in 

Pokemon Go. Alakazam also has the excellent ideal moveset of Confusion/Future Sight, which can dish out more damage than just about any other moveset. Sadly, Alakazam has a very low Stamnia stat, so don't expect it to be the best gym defender. 

Future Sight (Charge Move)

Element: Psychic

Damage: 120 

Damage with STAB: 150 

Charge Energy:

Move Cooldown: 2.70 seconds

Damage Per Second: 44.44

Damage Per Second w/STAB: 55.56

Defensive Damage Per Second: 25.53

Psychic (Legacy Charge Move)

Element: Psychic

Damage: 100

Damage with STAB: 125

Charge Energy: 

Move Cooldown: 2.80 seconds

Damage Per Second: 35.71

Dmage Per Second w/STAB: 44.64

Defensive Damage Per Second:  20.83

Legacy Alakazam vs New Alakazam (The video below)

Comparing 2 legacy ( with psychic ) and 2 new ( with future sight ) movesets. The zams are all lvl 30, and their IVs are listed in their names in the order of Atk/Def/Stam.1st battle is against a lvl 30 Chansey, though need to dodge the hyperbeam, otherwise they can't survive......2nd is against a greater than lvl 32 Blissey, and the final battle is against a lvl 30 snorlax.

Conclusion: Alakazam ( Future Sight ) is better than the legacy