They didn’t set the pet recharge cap as a nerf, they did so because the AI can go extremely high wire and break when recharge buffs are applied. Also, don’t think it’s just a cap.
Also I don't think it's a cap, as much as every single power for pets being flagged as "ignores recharge" (meaning they are also immune to -recharge debuffs.)
That being said, I think no one would consider Kinetics or Rad to be crippled without recharge buffs, the sets still deliver a lot of damage buffing, -regen and healing power.