SpeedPak is an amazing tool that could instantly solve many of the large assembly problems. By converting the heavy BREP entities in graphical objects, the largest assembly quickly converts into a user friendly model.
SpeedPaks are also great tool for protecting Intellectual Property. You can just send your customer 1 (one) file containing all he needs to see. You can also decide to leave some components as BREP, so your customer can use their faces for mates in his own assembly.
With the new 2017 enhancement of allowing the inclusion of Coordinate Systems and other reference entities in a SpeedPak, the circle is almost closed. SpeedPaks address now 90% of all the needs for most users.
The last thing that needs to be addressed is allowing the Interference and Collision detection tools to "see" the BREP data saved in the SpeedPaks. I do not understand why such tools currently completely ignore such bodies and faces. This functionality is absolutely needed if SOLIDWORKS wants to completely solve the Large Assembly Problem.
Vote on SPR 452788: interference detection does not work with Speedpak configurations.