The modern gangsta outfit, while much less cool, is more practical. Baseball caps and hoodies hide your face really well from any direction except straight ahead. Loose pants (unless TOO loose) give your legs more room to move without ripping out the crotch or crushing your nuts, and tennis shoes or basketball shoes are MUCH better for running and jumping.
Mobsters had the luxury of corrupting the cops. Nowadays the cops are too honorable and/or carefully monitored so the gangsta have to be able to run away.
What do you mean by "cooler"?
http://watchgodfather.com/pictures/1.jpg
http://s3.amazonaws.com/peat/images/big-gangsta-izzy-two.jpg
The mob did not have a "dress style" like today's gangstas who are mostly kids with attitude. Vito Corleone, Al Capone mobsters were people who created cities out of cities and even had cops on their payroll.