Yep, it's pretty obvious to most that I understand your point Rlwainwright. The Polk speakers are far from the best and most exiting speakers available in this gentleman's price range. The OP wants some new speakers for Granddad and the Polks may be old news. Maybe you are really just looking for an argument?
I think you should tune your room to your system, after you get the new speakers positioned where you want them Grandad. Might also wanna let them play for a few days first. I agree with Rlwainwright that room treatment is a top concern and should be addressed.
Caution: the Thiel may be too hot on top, IMO. And, not unlike planar speakers, they sometimes require a subwoofer.
BTW, I have spent time with Maggie 3.7! They sound great... in the frequency range that they are capable of playing in! Qualities are the ability to reproduce a lifelike presentation of the tunes with stunning mid-range and amazing dimensionality. BUT, they are lacking in the lower registers for my taste. Just something missing down deep IMO. This is all system dependent of course, but I feel like I got a pretty good helping of what these speakers are capable of. It's all about what you like your music to sound like...
Maybe check out speakers from companies like Vienna Acoustics & Von Schweikert also.