The simulation of aging related degradation mechanisms is a challenging task for timing and reliability estimations during all design phases of digital systems. Some good approaches towards accurate, efficient and applicable timing models at the register transfer level (RTL) have already been made. However recent state-of-the-art models often have to access lower levels of abstraction, such as the underlying gate-level netlist for each timing estimation and require to repeat every analyzing step if parameters, input signals or designs are changed. This work introduces a new RTL timing model concept that provides a separation of design analysis and aging estimation. It allows more efficient design evaluations with respect to aging. Although this is work in progress and systematic evaluations are still ongoing, early results indicate the applicability and capability of the approach to compete with recent models both in accuracy and efficiency.