I really doubt the DS708 hardware wise could not still program newer keys if the same # of Autel engineers and hours were put into the tool's software development as they once did when it was The Flagship scanner and The Pride of Autel. It was once hyped as the closest thing to an OE tool as you can get. Bet the GM Tech 2 or Ford NGS hardware and processors are even slower than the DS708.
The coding ability of the DS 708 on Autel's tool comparison chart is listed as Minimal where the regular (non Pro )MaxiSys coding abilities are listed as advanced.