At the same volume I can confirm that in my case the taller towers offered a more solid sound than the smaller ones, with more weight to it. Both really have the same kind of imaging, depth and soundstage but the smaller towers presented it on lighter footing even played at the same volume. Meaning the tall ones have more "presence" so I do understand what that salesman is talking about.
Can you have too much speaker presence?
My dealer says I’d lose too much speaker presence if I went to a smaller speaker. I’m not posting the speaker in question solely because I don’t want this to become an attack on them. I get it, presence means there and in the area, but can too much become and issue, especially when it is centered in a specific frequency range?