Speaker size and soundstage

w123ale, you have to close your eyes when you listen to remove visual ques from the equation. Tektons have a terrible image. Stay away.
There are only two sizes of sound stage, point source and line source. Line source speakers of which there are very few which are truly full range produce a large up front sound stage. Point source speakers, of which there are many produce a smaller "miniature" sound stage. 
You can adjust the situation somewhat with speaker spacing and listening position distance but if you like sitting in the first 10 rows you need to search for a line source speaker or partial line source speaker like Magnapans or any number of ESLs. The only full range line source that I know of on the market right now is the Sound Labs 845 or 945. 
Point source speakers are a dime a dozen, you have to chose your own poison.

If you have the space to pull the speakers out from the wall at least 3 or 4 ft, you might want to take a look at open baffle speakers such as this from Spatial. 

You have gotten very good obervations;

Flat repsonse speakers, on and off axis
speaker repositioning. The record mixer was likely mixingat a nearfield, classical 30/30 deg traingle position
room character upsetting that flat speaker
head position aligned with the tweeter and/or mid intersection
first wall reflections along that same ear level blur the original image
near field = more direct orignally recorded clues and information versus more reflections from your room

I have had 7' 6" line arrays and stand mounted two ways. The points above make the image, not the speaker size. Who listens 6" from your ceiling?

And we aren't in control of the recording Mixer's sound field positioning. Sometimes they try to make that flute stretch 8 feet between your speakers??? 

Happy hunting.

Magnepan 1.7's would do very well in your room. Soundstage,  Dynamics, all there. 

Check out Tannoy's. After a year of moving things around and learning more about speaker setup, I finally found the magical position for the Turnberry's. Since then, it's been heaven. Nice wide and tall soundstage and I have depth. Imaging is excellent. 15x20 room with not a whole lot of room treatment. My listening area is open and no clutter near the speakers or in front of the listening position. Gear is also down low and horizontal. It makes a difference. More room treatment and solid doors are next on the to-do list.