Wow, that's an unusual and interesting experience, thanks for posting it!
I do hope the blyxa recovers, it's one of my favorites and I hate to see it killed. I also wish I knew why so many people seem to lose ramshorns, when mine are completely unfazed. Do check ammonia levels for a bit - always wise when you have a large snail die-off, for any reason.
As for using this on a regular schedule as a mild maintenance treatment or preventative, I've been toying with it. It has potential. Excellent flow, without flow through the biofilter, is still needed for the H2O2 part. H2O2/Excel dosages will have to be reduced to the point where it still has a noticeable effect on algae, without any risk to fauna/flora, even if this means the effect on algae isn't so dramatic. It seems that will have to be found experimentally - and individually. As everything in my tanks is so resistant to H2O2/Excel, especially the staghorn which originally prompted the development of the "One-Two Punch", I doubt any dosage which proves useful for me would be useful to anyone else.