Using LPVs in medium-sized open environments is currently almost impossible due to the trade-off between size and quality. If the size is too large, there is too much light bleeding and a general lack of quality. If the LPV size is too small, parts of the environment won’t be lit and the transition between lit and unlit parts of the map is very noticeable.
In CryEngine 3 this problem is solved by having up to 3 cascades for the LPV. This seems to be a great solution to increase their usability and quality without a large impact on performance.
[Documented here (page 23).][3]
From what I understand, developing LPVs or real-time GI in general is currently not a priority at Epic. But I believe this is the single biggest issue with LPVs in UE4 right now and solving it would make it a valid dynamic lighting approach for current gen consoles especially.
It would be greatly appreciated if you could look into this!