Hi Karen,
Lesson plans are an effective way to guide you through the lessons you want to present. Being a veteran teacher you know what you want and need to accomplish with your students. So in effect you have lesson plans you just haven't put them on paper. Your college may require them and if so you can provide them by putting down what you intend to cover for that week. As to whether it will enhance your instructional style I don't know since you have already developed your style of the years. I would check with your school and see what they require in terms of lesson plans and then provide them so you can receive good marks all the way across on your evaluations.
Some schools require lesson plans as a result of accreditation and state certification requirements and this may be why your school is asking this of you.
Personally, I have always developed lesson plans so I know what I want to do and when I want to do it. I have not found them uncomfortable to use because I know I can make changes anytime I want and need to for my students.
Gary