What slicklizard said is exacly how I SL. I don't micromanage and tell each individual what kit to play, I just ask for a certain number of each kit as I deem necessary. This also depends on what base I plan to attack at first, and how we are going to attack it (ie take away enemy armor, or attack the flag and take care of infantry).
I try to think about things, but not overthink it. I also expect people to do their jobs. I have no problem kicking people that just ignore what I need or the squad needs. I think sometimes people fail to realize that we work from the commander on down and even though I may want to attack the next flag, I will recieve an order from the commander to defend a base. If I give that order at the current waypoint, I expect the squad to comply. Hey, if I have to, then you have to.
I hope you didn't mean to come across the way you did krosstika. If I call for an engineer and the squad doesn't have any and you die, I would hope you would spawn in as one and take care of the squads problem. If not, there is always the squad manage tab that can rectify that little problem.