our floor tried out team nursing. it didn't work for us, but another hospital in town has implemented it successfully. for us, though, the two nurses split the work - one did assessments (usually the RN since hospital policy was that an RN had to sign off on each patient's assessment at least daily), one did meds. but the med nurse, since they were renal patients, usually was WAY behind, even before she finished checking her charts. with 8-10 patients, several of whom had been there for many weeks and had 2-3 charts by that time, she was late beginning to pass the meds, and was VERY late by the time she finished. then you have a problem with aides/whoever not wanting to help because they figure there are two nurses with these patients, they should be able to do everything themselves (despite the med nurse being overwhelmed already). but the biggest problem with team nursing was the communication issue. this would be improved somewhat by experience, but one nurse would think the other was going to do something, while the second nurse didn't realize she was supposed to do it, so the task never got done. one nurse might carry out orders or deal with a change in patient status, and the other nurse might not hear about it for several hours, possibly, in the meantime, passing a med that probably shouldn't have been or talking to a doc and not mentioning it (because she didn't know it had happened), etc.
but some places do team nursing successfully. it takes a process that is well thought out and nurses who are committed to being a team instead of being a team in name and still trying to go solo, making it, in actually, harder for themselves and their partner.