What are you 'TRULY' Looking for in Loudspeaker...

When I read your question I didn't take it that you are looking for advice, just curious as to others thoughts. So here are my thoughts.
To the extent my budget and time allowed I have "studied" this in the most thorough way possible. Found Audiogon almost ten years ago and began buying speakers for "study" in with my ears. What I have found is that I want a speaker that I can listen to for hours without thinking about the speakers, system or any other audio related gotchas.
Although I can't imagine not looking for something better, I do believe I have found what gives me all I want. I can listen for hours (if I ever have the time) and while doing this I keep turning it up just a smidge more without it irritating me. This isn't possible with most of the speakers I've owned. In fact, I recently purchased a pair of monitors valued at more than 3 times my current monitors and I kept turning them down to save my ears. They had way too much of the "audiophile" flavor.
How many speakers have I owned? I swear I could not answer that question with certainty.

For the reproduced sound as close to unamplified vocal and acoustic guitar including bass guitar as possible. And I pay attention to size and price.

Great imaging,great,stage,fast bass,natural sounding speaker that disappear just like my MAGICO MINI 2 the best.

Natural tone
100% coherence from highs to lows -> solid timing-> musicality
Weight AND speed -> lifelike timbre, presence, immediacy
Pinpoint imaging -> instrument separation

Planars lack in imaging, single driver speakers lack in body/weight and tone on both extremes, 2 way dynamic speakers either in the bass weight and / or midrange transients. Most speakers have problems with coherence in mass and speed, especially ín the bass region.

Only the 2 way transmissionline speakers (good coherent bass speed but without weight) or 3 way speakers with small woofersize around 5" (-> speed, accurate timing, midrange driver got to have the same size) worked for me so far.

Not to get crazy here, I assume that you mean listening criteria not physical.
#1 Tonal Balance
#2 Soundstage (do they disappear)
#3 Imaging (can I point to everything on stage)
Then I assume mated with the right electronics that have synergy with these speakers that the combination sounds like music.
There are a few more factors but these 3, I am somewhat fanatic about.