Have you ever changed speakers to expereince a different "soundscape" or presentation??

I have two pairs of speakers (Maggie .7s and KEF LS50s) for just that reason. When I need a change, rather than making a purchase, I just switch out the speakers and that change appeases me until I get the itch again.

I do this quite a lot! I'm a sucker for soundstaging, so trying out different models to find better and bigger sound is often a pastime - though it seems to sometimes be at the cost of detail for some reason... Dynaudio seems to be the best for big, "detached from the speakers" type sound, with a generous sweetspot so far.

Definitely yes. The more you fine tune the speaker/room interface the more you can approach the original sound.

For me the acid test that any adjustment is moving in the right direction is whether it increases the diversity of scale and tonality in the reproduction. As you get things more optimized there should be greater variation in instrumental scale (i.e small instruments sound small and localized in space, and large instruments or massed strings say take up the appropriate space). This is true in two (L-R, F-B) and even three dimensions. In addition it should be easier to differentiate the tone of instruments, try separating strings in a string section, or isolating back up singers for example.

Sometimes this can strike you as a negative as the sound of something leaping out at you, spotlighted in a way, can be appealing but it's not natural (I'm of course talking about acoustic recordings here, studio artifice can create lots of effects but the well setup speaker should excel at teasing them apart).

I too have multiple sets of speakers.  It might be part compulsion, but it is also the regret of letting a speaker go and losing that sound.  I like changing it up.