Microservice architecture has emerged as the dominant architectural pattern for modern software systems, offering scalability, modularity, and fault tolerance. However, its highly distributed and interdependent nature makes evaluating architectural designs and proposed changes increasingly complex. This paper presents MicroViSim, a lightweight tool for simulating load and visualizing service dependencies and performance metrics in Kubernetes-based microservice systems. MicroViSim enables developers and operators to pre-evaluate new or evolving architectures prior to deployment by generating service dependency graphs, performance indicators, and load simulation results from user-defined YAML configurations. These visual insights help uncover potential bottlenecks and performance risks early in the design phase, thereby reducing future maintenance costs and the likelihood of system failures. Experiments using a real-world microservice application, Bookinfo, demonstrate that MicroViSim effectively identifies architectural weaknesses and supports informed deployment decisions.