Should I upgrade my Advent 5002 speakers?

How about this: the speakers that impressed me the most over the past several years have been the Ohm Walsh Sound Cylinders! I bought a seond-hand pair quite cheaply. They may be the best sounding and better than any of the other speakers in my collection! And this includes my Quad 57's! Stunning 3 - D room-filling sound from any spot! The performers are right there in the room! I am impressed! Ohm Acoustics in Brooklyn, NY can probably build you a pair of Sound Cylinders in the finish of your choice. You can contact and speak to the owner John Strohbeen. Ohm has been established over 40 years!

Except for the size part, it sound like you might like Vandersteens.

Stand mounts...if it were me I'd go with MA Silver 100s. But that's just my personal taste.

Second the motion on checking out Ohms. I have a pair of 1000s and they are great. Ohm also has a 120 home trial period, so you can return them if they don't pan out for you. You are just out shipping. 

Should I upgrade my Advent 5002 speakers?

Yes, you should.

I am a huge fan of the Large Advent. Henry Kloss worked some magical engineering into the voicing that still amazes people today. That said they are not the last word in definition and dynamics. Time moves on. Footprint and architecture-wise the SourcePoint 10s bear more than a little resemblance to the Advent, from the 2 Ft3 box to the 10-ish inch woofer and slightly oversized tweeter to enable a lower crossover point. All straight from the Advent playbook. I have admired Mr. Jones work for a long time, and he doesn't do sloppy work.. But, there is another speaker i would seriously consider: the Monitor Audio Silver 500 7G. There are several reasons why Stereophile put this on their Class A list, at a price about 10-20% of most of its peers.  It is really, really good overall. It is accurate, dynamic, has great bass extension, is pretty easy to drive, and is simply provides a listening experience to which you want to return - often. Although a tower, it takes up no more room than the SourcePoints on their obligatory stands.

Rather than repeat what others have said, for both speakers, read the reviews, and find a pair to audition.