Wizards looks promising. I'm still really iffy on the whole "health as a buffer and then strenght as actual damage, with critical damage rolls every time" thing. Call me old fashioned, but I like straight up hp or chunky salsa more. Not that that really matters much.
The health as a buffer then strength as actual damage is probably the most old school version of RPG health there is. Most OSR games still use it; like "The Black Hack".
In any case, there's also an idea I've been toying with for a long time called "FLESH" which involves players starting as boring old humans and becoming more powerful by replacing their body parts and organs with weird inhuman guts that give them special powers and abilities. Sort of the same modular construction as the pacific rim game but on your specific character and much more gooey and cronenbergian.
Old fashioned straight HP goes right back to the original D&D, if not further.
Flesh sounds kinda like a human version of the construct game that was put up for vote alongside oro and ERII. It was the one I preferred over the others. No one else did.
I'm not really into a Xan Arena idea. ER works in part because it made room for multiple playstyles and goals and whatnot. the ending read like the ending of a real sci fi (soft sci fi) series, because of the varied characters, goals, and methods to achieve those goals.
I like Wizards, but not straight up arena dueling because, unless you trickle players in constantly, it starts out with a lot of players, and then over time fewer and fewer players are able to participate, leaving the others to wait and twiddle their thumbs . And if players trickle in, there's the risk of power apartheid. Of course, I have little to no familiarity with perplexicon, and I hear that was highly successful, so ...
Maybe i'm just holding out for a flexible, long term, immersiom experience. I don't know.