Lack of project prioritisation

Lack of project prioritisation, Project managers feel that big projects carry more weight than small projects thus causing the small projects to suffer as they are not able to manage their time and to prioritise.
Inefficient resource allocation, it is hard for them to keep balance in allocating resources and weigh between different projects, as well as to properly managing the time allocated for each project.
Small projects suffer in a sense that when the project managers have these projects, they get stuck in one functional department, which leaves them not feeling in charge and helpless. This environment in the workplace, especially given the fact that these departments have to collaborate work efforts to achieve the desired results, created a lack of motivation from project team members to share ideas and solutions.
The roles and responsibilities have not been clearly defined by the responsible team member heading the project. This has resulted in line managers not acknowledging that it is the responsibility of project managers to make decisions on commitments with clients based on agreed specifications and project requirements as prescribed by the company policy.