Curious how you have the Side Heights set up at the AVR?
Do you have them set as Top Front or Top Back?
If you have them as Rear Height, you should absolutely move them to correct placement..
For the true Rear Speakers, I agree, they are too high as is,
perhaps even a little too wide. If you put those on stands and aim them toward the MLP you will definitely experience a better surround field. Same would count if you are able to get better placement for the Surrounds on Right and Left.
Any overhead Speaker placement is predicated on having the Bed Layer as dialed in as possible. For Speaker placement, the ideal is placing be Angle to the MLP.
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Great example of placement using angles is like this:
For your Mains, if you are 8' away, the closest the Speakers should be is ~6.5 ', measured from Center of baffle to center of baffle. That would be 22º from MLP. With the same 8' listening distanced and the 30º angle, the widest you would place the mains is about 9' apart on center.
I know and respect that we all have to make some compromises in our setup. At the same time, the closer you can get to these placement parameters, the better an effect you will experience.
Same goes double for the Height and Top placements for Atmos/Auro. IIRC, Heights are supposed to be the same placement as L/R Main, but be somewhere between 20-30º above your ears, front and back.
If you are using Atmos placements for those Side Heights, you need to find the correct angles for proper placement.
Maybe not a deal breaker, but I can say with absolute assuredness that the placement angles do make a difference! I used to have my Rears mounted high on the back wall over a closet door. Since pulling them down to proper placement, I am reminded about why Dolby give such specifics.
If you haven't seen the Dolby PDF, it's a bit dry reading, but the info is worthwhile.
Cheers!