Personally, I'm leary of wireless thermometers. I've heard too many horror stories, and my wired thermo works great. That being said, if you're comfortable with them go for it.
If I was in your shoes, I'd look for a used Weber. If used is not an option, get a new OTG. The OTG is worth ghe extra money, over the OTS. A Weber will replace your grill that is dying, plus give you a UDS lid. You can grill on the Weber without the lid, while your UDS is smoking away.
If your wife is concerned about the quantity of cookers, show her our signature lines. Most of us have multiple cookers, and we generally use them all. Maybe not all the time, nor at the same time. We have 3 22.5" Webers, and use at least 2 each time we cook. My wife said we couldn't get anymore, but she looks for used ones, constantly.
Good luck. Let us know what you decide. Either decision will serve you well.
"Grandpa, you make the best meat, EVER!!"