You know, I share very similar sentiments. I have been reefing for 25+ years and have MANY MH/T5 fixtures, reflectors ballasts and new bulbs that are simply collecting dust in storage. I thought about employing them almost a couple years back when I jumped back into the hobby, but curiosity got the best of me and I went with the Radion G5's.
Are they better than MH/T5? No, they are not. When it comes to lighting, spectrum and growth I would place them on just about equal footing, with T5's taking an edge with growth. Ease of use and maintenance is where the Radions shine. I like that they're easy to clean, ramp up/down, and adjust to my personal preferences. The slim form factor is also great when you need the reef display to take up as little space as possible.
I currently have a new Waterbox 6025 in storage that should be up and running in the next few weeks. I thought long and hard about what lighting I would use and ultimately decided to add a couple more XR30 G5's to add to the two XR15 G5's I already have. The deciding factor was that I did not want to have a canopy over the tank nor did I want to deal with the heat generated by a couple MH's. Had the tank been placed in-wall it would have been a no brainer to use the MH's in Lumenarc III's.
I agree with your opinions on the current state of the hobby. The coral craze has gotten a bit out of hand. Nowadays, I don't chase corals. At one point, I had just about every desirable coral and you know what, they were no more different or special than the OG's that you find for $10 a frag.
The one trend that blew my mind was the use of only dry rock to start up a reef. People wonder why they have issues and are dealing with Dino's, al of which are likely due to the lack of biodiversity in the system.
But hey, don't fret. The glory days may be gone but quite a few of us OG salties are jumping back in. We're going to herald in a new golden age of reefing. We'll show these whippersnappers a thing or two!
-Sonny