Hello,
Overriding the controller might not been the best approach. But you can see to have your own controller for your specific actions.
Afterwards, the Cart API system have function to add products into a cart so, if you format correctly the data you should be able to use that function to add a product into the cart from the wishlist data you have (and not just perform a "move" like it is right now).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.