I am quite new to this company which has a very small department for my particular profession. Everyone in this department comes from other professions and they have poor knowledge about it.
There is one coworker which is working on similar projects as me and very often I end up working with him. Because of seniority he has the final say in pretty much every decision along the way, and they are usually poorly thought decisions which only cost us more work down the road.
Recently my boss has offered me more responsibility and I am willing to accept the offer, however I would like to request that I do not collaborate with this coworker anymore, that is I would like to manage my own projects and make my own decisions.
How can I achieve this without alienating everyone at work (to ruin the relationship with the coworker and to appear arrogant to my boss)?
Trying to win over the hearts and minds of the people involved by showing them why my choices are better is not really an option because of a "just get it done" mentality.