New arm lift technologies that would lessen scarring?

There are no new surgical technologies to lessen surgical scars from arm lifts, however all of the usual principles applied to getting a good scar must be diligently followed.
Good surgical technique, careful suturing and appropriate care of the incision are important. The things a patient can do to help lessen scarring are to have surgery when they are at a healthy weight for the surgery, good nutrition, and use a compression garment after surgery.
The skin at the inner arm is very sensitive to scarring, so it is difficult to predict how well your scar will do in advance. There are many modalities that can be used to lessen scars after surgery, such as silicone scar pads, topical ointments and creams as well a certain lasers.

Depending on the degree of skin laxity you have there may be options to the traditional arm lift. You may be a candidate for JPlasma or BodyTite. If you have moderate to severe laxity though, you'll likely have the best results from a brachioplasty.