1) Riveron is (or at least was when I resigned) very top heavy at the Director and Senior Director levels, which are the highest delivery levels before you are an MD (partner equivalent). This has led to very talented individuals stalling out in their careers. When raising the issue with performance advisors or MDs, responses were usually vague such as "you just need more reps" or "you're not quite there yet, but we'll go for it next year" without actionable feedback. I believe this is a product of the strong talent as well as growth that is a little more anemic than expected, leading to top-heaviness that is hard to overcome as someone who wants to keep advancing.
2) Leadership between the C-Suite and the rank-and-file MDs (partners) was often opaque and a bit of an "old boy's club". If you break the inner circle and get the folks who quietly hold all the power speaking your name, you will advance quickly. If you don't get those opportunities, you will lag behind regardless of your talent. This was especially challenging, as this level of leadership is the one that dictates compensation, advancement, and project opportunities.
3) Riveron's inorganic growth through acquisition has exacerbated issues with advancement and compensation, as some of the new leaders they bring in through acquisition end up favoring "their people" from pre-acquisition over those at Riveron before the acquisition. These acquisitions have in many cases led to the installation of acquiree leadership within Riveron's leadership structure with little subsequent oversight, causing friction at all levels.