What should you hear?

From your description, it seems like you are getting good stereo imaging.  Certainly, your Vandersteens are capable of delivering good imaging. The subject of what constitutes good imaging and how to achieve it is quite complicated.  Almost all types of speakers can deliver great imaging, so it primarily comes down to speaker placement, the placement of the listener, and room acoustics. 

Speaker placement is very important, and the only way to optimize placement is by trial and error.  If you think you have decent imaging already, make tiny adjustments in speaker placement, and on toe-in, and even how much the speaker leans (rake).  Generally speaking, if you don't think the center image seems tight and prominent enough, you should try increasing toe-in so that the speaker is pointed more directly at you.  The tradeoff is that the sense of image width or envelopment of the listener decreases with more toe-in, so you are juggling compromises.  The rake angle will determine how high central images seem to be; generally speaking, the more the speaker tilts back, the higher the image seems to be.  Moving speakers further out into the room from the wall in front of you will tend to increase a sense of depth, and moving speakers away from side walls will tend to make the sound seem to float more freely away from the speakers.  But, sometimes, interference from a nearby wall can artificially create a sense of a wider soundstage, and you might actually like that; again experimentation is in order.

I try to avoid having a large flat surface, like a coffee table, between my listening position and the speaker; if that can't be avoided, have enough stuff on the table to break up the reflections off the surface into something more random.

I agree that imaging on some classical orchestral recordings can be quite impressive.  I like recorded music for that aspect of performance.  But, arguably, it is not that realistic because you almost never get the kind of precise instrument placements one has on recordings when hearing the music live.  If you close your eyes at a orchestral performance, you really don't hear as precise an image; you use your eyes to get the placement.  I don't care that much that most recordings are, in that sense, unrealistic, because I like what I hear.

@larryi --

I agree that imaging on some classical orchestral recordings can be quite impressive. I like recorded music for that aspect of performance. But, arguably, it is not that realistic because you almost never get the kind of precise instrument placements one has on recordings when hearing the music live. If you close your eyes at a orchestral performance, you really don't hear as precise an image; you use your eyes to get the placement. I don't care that much that most recordings are, in that sense, unrealistic, because I like what I hear.

Important point raised regarding the perceived experience of live music vs. its reproduced state in front of a home stereo. In that sense and on a broader scale it could easily be argued that the cultivation of reproduced music tends to be something of its own rather than more authentically emulating a live reference (un-amplified or not). We're not always given that much to work with in light of the nature of a range of recordings, but that being said, and irrespective of the nature of said recordings, what is sought after is usually more of a magnifying glass placed over a limited area on a canvas rather than seeing the scope of a bigger picture - with all that entails one way and the other..

People that attend live musical events and fail to locate instrumental voices, via ear, should spend a bit more, on their seating.        Of course; it helps to know something about the hall/venue, the seating arrangements, and acoustics.         For acoustic Jazz, Blues, Chamber Music, etc gigs: get there earlier and pick a seat, that allows for a balanced sound stage, imagining where binaural mics might be placed, if one were recording.                    That’s all assuming venues with decent acoustics.

@rodman99999 
I agree on seating position in a concert hall or club and the acoustics. Here in Philly we have a mega million dollar overdamped concert hall which is such a shame. The orchestra moved from a 150 year old venue with excellent sonics.

As stated above, the recording of an orchestra may not give a true reproduction of the live event. Depending on engineering and recording techniques, it may sound flat and closed-in or may sound open with great depth. I prefer not to compare it to live, but to enjoy a great performance with the ambience of a concert hall. I like my listening spot to sound like I'm sitting in mid-hall orchestra seating.

@rodman99999 --

People that attend live musical events and fail to locate instrumental voices, via ear, should spend a bit more, on their seating.       Of course; it helps to know something about the hall/venue, the seating arrangements, and acoustics.        For acoustic Jazz, Blues, Chamber Music, etc gigs: get there earlier and pick a seat, that allows for a balanced sound stage, imagining where binaural mics might be placed, if one were recording.                   That’s all assuming venues with decent acoustics.

From my chair it's not about "fail[ing] to locate instrumental voices," but rather that the sonic nature of a live acoustic event deviates intrinsically from a reproduced ditto in a home setting, and that also in the sense that the precision of instrumental placement that can be found in the latter isn't as pronounced in the former. These impressions are based on a variety of concert venues with very good to excellent acoustics, positioned mid-hall or the 3/4 section of the seating rows, as centered as possible. I'm a fiend when it comes to finding the proper seating position, mind you. 

Still, despite the fundamental difference of presentation from a live acoustic event (less so an amplified one), it's my go-to reference when trying to humbly approximate its traits/characteristics via the home stereo, and not the other way round.