This shows clearly that there is some caching going on (the second time around the data is already in memory).
I guess the required changes for preloading at least the very first data block of each slice aren’t technically that complicated to accomplish.
But the firmware has maxed out its available code space. So to fit in any new feature means rewriting and optimizing code somewhere else to squeeze out some free bytes for the new code. As you can imagine this isn’t an easy task.
My guess is that it won’t happen. While it’s very likely that we see more firmware updates in the future the list of possible improvements is long and there are also still some bugs lurking around since years needing attention.