I doubt that a big cap bank will improve the bass response. What a big cap bank is supposed to do is provide instantaneous energy when the program material calls for it (like sudden dynamic peaks).
In general I find the bass weight of 3118 lesser than two other amps I compared it to (this is only in relative terms - it has enough bass heft in my system for my taste), but the deficiency in bass weight is in some way made up by the texture of the bass. It brings out the tonality of the bass much better, for example, than the LM3886 based MyRef Rev C amp (though MyRef has more bass weight).
Guess that sums it up nicely :sad: