We've been using dawn for years in the home furnishings business, it is not harsh when deluted. 90% of dirt and grime in a car is oils from your hands, hair, petrolium based scuff marks from rubber shoes and such. The dawn is able to cut that grease effectively without being harsh on the leather. Leather in cars...even Lexus is usually a lesser grade of leather than what is used in your home. The car endures harsher temperatures and more elements than a leather sofa. The top coats applied to the leather are tougher and thicker, therefore you get more top coat than leather that is embossed with a leather grain. Lexus leather is a top grain, but heavily pigmented to protect it. Analine died means it is died all the way through the hide.
So, dawn deluted is not harsh and works very well. Woolite will take much more elbow grease, but is a very effective cleaner as well, it's not as good with getting the grease and oils off.