There are many ways to consider that point. Referencing dlls/includes/assemblies is quite traditional in most programming languages, and sometimes just for a one or two functions. At least in DBP plugins you get helpfiles, in some development kits the only help you get are function and parameter names.
On one hand the plugins should be designed to be
useful; therefore to only use a few of the functions within a hundred would reflect a somewhat useless plugin; and I am sure you will be using many Matrix1 functions in future; functions like Max/Min, Call Function Ptr/Name and Get Limb Name and RGB (with alpha channel reference) are a few Matrix1 functions you'd likely find useful in many situations; and these just scratch the surface.
Another thing is, sometimes one or two functions are extremely important.
Would it be a good thing to have all functions as part of the DBP standard package without extra DLLS? I personally do not know. Would it be good to have all the 'useful' functions included as standard; now that wouldn't be realistic because what is useful for one person is useless for another.
With that said, probably Matrix1, Sparky's collision and A2D should be part of the standard package because it is highly unlikely for anybody to argue that these three are the most important DBP plugins for most projects; some may prefer D3D Func over A2D, some appear to think installing Matrix1 is not going to benefit them; and there are alternatives to Sparky's collision. Personally I use Dynamix (PhysX) for collision but still end up using Sparky's for simple purposes.
With vector exist, that should have been put in the standard package; but the creator of DBP is quite occupied with FPS Creator Reloaded; things like DBP commands are probably at the bottom of the list, although FPSC is created in DBP, perhaps we might get more commands this year.. who knows.
I personally wouldn't worry about file size or dll installations. In this broadband high speed internet age, even if you optimize; people will still complain about your file size, then they will spend the rest of the evening watching 1 GB worth of YouTube videos and will install a million DLLs without realising it throughout the course of their lifespan.
