At the end of the day, two of the most fundamental components of any successful project must not be short-changed: people and time.
Better to have a project take longer and to involve more people rather than involve less people and rush.
With more people we do not mean more people working on the projectt but more people being involved with the project. In other words, stakeholders. The largest group being the end users, those who will be impacted by the project output most. The success of the project, in terms of acceptance and adoption, is greatly driven by the people who will, or will not, be using the end product the most.
Adding and/or increasing stakeholder involment throughout your project will very likely add to the cost as well as to the duration but it is more than worth your consideration.