I think when DTSX Pro is finally more widely in use, Wides will become much more active. I think for many, currently, it is hit and miss, like some of the overhead placements can be.
Also, the size of the room and how you are able to place Speakers will have a serious impact.
A standard 5- or 7-channel bed layer could be fudged a little to suit individual arrangements. Yes, efficacy still comes into play as to whether you get a convincing surround field, but you could
fudge it a little.
Most of the failures I've caught glimpses of with Overhead placements come about from poor choices. Add to that the state of inconsistent upmixers where there are many reports of Top Middle not working in one soundtrack, but another cuts out Top Front and Top Rear while sending the signal to the TMs.
I think that they will become more useful as HT people are most assuredly interested in them, even if using something like the Monolith Wide Synth feature on the HTP-1 (where the processor creates a Wide output based on combining the Main + Surround signal to send to that position). (I've also heard that the signal in this case can be unbalanced and some report cutting the output by several dB to get those Wides to blend and integrate properly.)
Anyway, I think there is definitely too much rush to keep adding more Speakers, more channels. It's a good thing when it works.
Not so great when it doesn't.
To that end, unless you have a processor that can specifically support them, you are more likely than not going to get shorted on the performance aspect. Again, DTSX Pro is supposed to include upmixing to Wides, as I understand it, but so many processors still have yet to implement it (leading me to believe [speculation] there is something buggy about final implementation or required processing power that simply isn't going to be supported until the next generation of devices).
After all, if Atmos mixes and upmixing is still somewhat of a chancy affair, do you think the resurgence of Wides is going to actually come off without a hitch? ...Or 5?
And if Atmos mixes still don't include ability to utilize all locations, how long will it take for mixes to start including more than the most standard 5-channel info?
Lastly, going back to room size and proper placement, I suspect that you likely need more space to place these properly. Not saying it cannot be done with a shoehorn, but I [example] probably only have about 8' linear from Main to matching Surround. And, in an 11'w room, where would you try to place those Speakers?
My guess is that to be more effective, you want more distance from Main to Surround, (perhaps 10-15') as well as more lateral distance to work with (perhaps more like 15-17' wide). You need your Mains a minimum of 8' apart (mine are 6') and you need space to separate Main from Wide to Surround.
Here is the Dolby angles for a 9-channel Bed Layer:
Such is the situation with Atmos Placement that you really need to pay attention to the Angles to get the full effect, and Atmos raises the bar in placement by making you get the Height appropriate as well as Left/Right, Front/Back.