Most professionals have custom blades made for them when they are ranked in top 50 or 100 to my knowledge. ZJK uses a custom viscaria that's rather heavy unlike the commercial blade. Timo also has a weight requirement with his blade. For the most part here's what most offensive players will use and what most defensive players will use.
An offensive player is looking for a medium to heavy blade that has harder cores and inner plies with a carbon ply and then usually a softer ply for touch, but also for added catapult effect when the balls energy rebounds off the core. It is the easiest way for players to attack the ball because they can generate much more power and speed through technique rather than through the equipment again this is a generalized statement that most offensive players are looking for.
A defensive player is very often looking for a soft to medium blade that allows for extra control and spin variation, but again is looking for something that will either help their lobbing, fishing, chopping, or whatever they use to defend with.
An all-around player will most likely try to find a blade regardless of hardness that is to their liking, but gives them the added benefit of both attack and defense.
Many players will look for the perfect blade and the perfect set up, but with a solid foundation in basics you should be able adjust your stroke and play with just about any set up. Remember to look for a set up in blade and rubber choices that plays to your strengths, but does not diminish your weaknesses.
