You and I both know a FDR is a pain in the ***.
Which is more of a pain? Living with a phone that has had disappointing battery results or trying an FDR to see if it's the solution? You've been complaining about battery life for many weeks now. At some point you could have done an FDR, and at the very least you would have ruled out that being a solution to your problem, and at best you would have solved your problem.
(FWIW, FDR is not much of a pain for me. I use an app called DropSync to synchronize key internal storage folders to Dropbox automatically, so after doing an FDR I just copy the folders back after the apps are reinstalled and reconfigure sound and notification settings for my apps. [One of those folders that's backed up are my custom ringtones and notification tones.] I also back up text messages and call logs using SMS Backup+, so those are always up to date. I keep a pretty stock home screen with only one screen, so that's easy to reset. Google needed to improve this on Android years ago,; iOS is a piece of cake by comparison to restore from the equivalent of an FDR. I do this not only to make FDR not too much of a pain; I want to be able to get myself up and running quickly if my phone is lost or stolen, or needs to be warranty replaced, or when I get a new phone.)
SUA is a *little* risky - flashing the phone is always risky - and I honestly don't think it will solve your WiFi problem. I think that your problem is due to one of a couple of things:
1. You have an app that has the permission set control the WiFi radio
2. There is a bug in Lollipop, or a permission in one of Google's apps, that does the same.
If it is number 1, it will not be solved by SUA. If it is number 2, it will not be solved by SUA, either, but likely will by M.
I suppose it could be:
3. An installed app has corrupted data
Guess what will solve number 3? (Either FDR or uninstall and reinstall every app until you find the one that caused the issue, if there is one. And if it is a preinstalled app, only the FDR or wiping data for all of those will help, and than can be dangerous for some system app.)
But, you can try it, it's probably benign and maybe I am wrong about it solving your problem. But, again - the Marshmallow upgrade is going to do the equivalent of SUA when it comes (i.e, replace all of the system files and firmware files with stock copies; the M update will touch every one of those), and we know it should be coming soon. Here's the thing: if you are unrooted, you cannot change the system apps or settings through normal operation of the phone or using apps anyway - the system partitions are read only (and they are write protected on Motorola phones even if you are rooted.) That's why I think SUA will make no difference - if it's some esoteric setting, those are set in the data partition, and those are only changed by clicking the right setting, or - yes - a factory data reset.
You've been pointing out battery issues for weeks now, so I'd suggest that rather than do the SUA now, you may as well just wait a week or two more and then take action after the M upgrade if the problems persist. And then do the FDR, if you don't want to try it now.