LOD popping is quiet distracting for most Objects in the game. Especially the trees, buildings, rocks and vehicles.

LOD blending/morphing technique would resolve lot of annoying flickering/popping issues.

Example:
http://www.digitalrune.com/Support/Blog/tabid/719/EntryId/195/LOD-Blending.aspx

Gif: http://makeagif.com/i/GMxuDw

There are several strategies to minimize popping and create smooth transitions:
-Geometry morphing: The high-detail geometry morphs into the low-detail geometry and vice-versa by collapsing edges and removing vertices. This approach involves a lot of overhead at runtime. Because of this complication it is seldom used in games.
-Screen-door transparency, as described here, can be used to blend between LODs. This approach has a very small overhead compared to morphing and it is not limited to meshes.