Pads length in Altium footprint wizard
There are two ways:


Start over in the wizard and make a new part (easy)
Use careful selection and movement to do what you did for all pads (not hard but not simple)


Are you familiar with the PCB Inspector window? It gives you access to the properties of everything that you currently have selected.

A way to approach this might be:


Select all the pads on the left side
Edit the x-coordinate for the pads in the Inspector to pull them away from the part center
Increase the length of all pads in the Inspector (probably increase by 2x the distance you moved it in step 2, which puts the pad's inside back where it started)
Repeat for all the other pad groups.


Note this can be done in four selection steps, if you select what you need and then edit in the Inspector as a group.