The time for a popup dialog to animate onto the page is surprisingly slow. And when you are editing many records, contributes to making that process longer for no valid reason. Delivering the content in realtime is always the best option - keep it simple.
Performance is a top priority as we always take great strides in ensuring a quality experience across the entire application. As noted, we do have animations on popup dialogs, however, these should not have an impact on overall application performance.
The issue with the animation is often not one on overall application performance, but of perceived performance, especially when combined with other latencies.
i.e. I'm in New Zealand, so have about 200-250ms latency into the US (where I assume Aha! is hosted), so any dialog that does a resource request already has a distinguishable pause, which the animation then adds onto.
If the resource request is particularly slow, this results in quite a jarring delay in the dialog being available for use.