Hi Zoran,
The part you attached was created in 2009. I used an internal debug tool to migrate all features to 2018 (the last saved version). Now, the edit and update seems to be fast. Could you take a look?
Regarding the difference between Extrude and Emboss, there is indeed some difference. Extrude takes a profile to sweep along the sketch normal direction in a given distance. Emboss, on the other hand, uses the profile to split the given faces and then thicken the split face to the given distance. For planar faces, the resultant geometry from either feature is the same. But, for non-planar faces, they are different. Certainly, Emboss is slightly more compute intensive. However, there should not be drastic difference. There could be bugs in the past leading to one being much faster than the other.
Regarding LOD and Design View Rep, I personally believe there was miscommunication and misunderstanding. LOD was designed to be memory management tool. It was essential to enable users to design assemblies requiring more memory than allowed on 32-bit Windows. However, for some reasons, some users have tried using it for Configuration purposes. For some cases, it does work. But, for most cases, LOD is not an adequate Configuration tool. It cannot alter BOM or PartsList. Changes to multiple LODs cannot be saved at the same time. In drawings, each LOD has to be loaded in the memory if it is referenced by drawing views.
Starting from Inventor 2016, you can specify Design View Rep as a filter to deduct invisible components in Drawing PartsList. So, you can use DVR to control part quantities in the drawing. However, there is still only one BOM table in the assembly as single source of truth.
I can tell that you are unhappy with using Inventor. Inventor is a tool of choice. It has its own strength and weakness. But, we are committed to improve it consistently. If you have any further questions or comments, please feel free to post them here. We have experts around the world answering questions around the clock. You are also more than welcome to contact me directly ([email protected]).
Many thanks!