It depends what you mean by "categorizing". Working on large software implementations (40 consultants and significant number of client staff), we had many roles which had to be fulfilled. Someone had to architect the solution, business analysts had to gather requirements, configuration specialists manipulated the software to meet the requirements, sometimes engineers/developers were needed to do something non-standard, reporting specialists used the report writing software to meet reporting requirements .... I think you get the picture. Each role had a unique set of skill requirements and billing rates. Project managers had to work with resource managers to determine which consultants would fill which roles. If this is what you mean by "categorizing", it is a necessary function of the role.
For smaller implementations, this was typically already done -- the client had functional teams and consultants became an extension of the team. If this is within your smaller company that is not as well organized, you will again have to decide how to best fill the roles.