A modeling tool not only helps users express their ideas and thoughts but also serves as a communication platform among domain experts, designers, developers, and others practitioners. Existing modeling tools have shortcomings in terms of supported functionality and situated usability or do not meet the needs of users of varying levels of expertise. To facilitate improvement of such modeling tools, this research begins by identifying common problems in existing tools and proceeds by borrowing concepts from grounded theory to develop a framework of redesign guidelines. A case study illustrates how this framework can be used by applying it to MetaSketch, a metamodeling tool. The study employs multiple user experience research methods, including usability tests with paper prototypes, observations, interviews, and contextual inquiries. A set of core tasks and two significant modeling approaches were identified that directly influence interface and interaction design for modeling tools.