The shift in design philosophy from prioritizing simplicity and small scale to allowing for complexity and larger configurations, as long as performance remains unaffected, marks a significant evolution. This change illustrates an ongoing effort to balance speed with the system's ability to handle more intricate operations. However, challenges such as implementing sibling eviction in version 3.1 underscore the complexities involved in expanding support for configurations involving multiple clusters. These challenges highlight the limitations within the current system architecture or algorithms, indicating that substantial enhancements or reevaluations of foundational principles might be necessary.

The issue of "top block" style systems is emphasized, noting the importance of ensuring all resulting clusters meet this criterion to prevent trivial manipulation through the creation and cycling of clusters. This requirement adds a layer of complexity to state transitions, suggesting that achieving this consistently might require rejecting certain transitions that fail to meet the standard. Furthermore, the introduction of sibling eviction in version 3.1 brings to light the difficulties in extending support beyond two clusters, pointing to inherent system limitations that complicate straightforward improvements.

Evaluating transactional policies in post-cluster mempool environments reveals efforts to evolve these policies towards greater flexibility, compatibility, and usefulness while maintaining backward compatibility. The V3 policy, with its constraints on parent-child transaction sizes and limitations on batched CPFP and chains larger than two transactions, illustrates the challenges faced. The proposed V3.0.5 aims to adjust these policies by relaxing some restrictions, thereby reducing guesswork around CPFP size requirements without overly simplifying sibling eviction. This proposal, however, raises concerns about vulnerability to sophisticated attacks.

The V4 series introduces different policy iterations aimed at removing topological restrictions and supporting features like ANYONCANPAY, while also addressing pin resistance and the propagation of non-top block transactions. The hybrid approach of V4c, which combines elements of V3.1 and V4, seeks to balance pin risk with user experience by relaxing conditions for non-top block transactions under specific scenarios. These proposed policy evolutions reflect a broader goal of creating a more adaptable, robust, and user-friendly transaction policy framework capable of accommodating the dynamic nature of mempool landscapes.