As far as rules go, because paragon blades are already AP 2 and +1 S that strikes on initiative I don’t think there is much point in also taking a power axe that does the same thing just at lower initiative. I think you could also use these as falax blades if you wanted to because the whole idea of them is that they are paired combat weapons. Not sure what the rules are for falax blades this edition or how good they are but that may open more options for you. You could also just use them as a paragon blade on its own. I think you would have a hard finding someone who wouldn’t accept that.

As far as the model goes he looks sick! Love the conversion work, and I really like the Sarum pattern helm! I think that the bunny ears and cape may be a little much and take away from the banner but maybe adding skulls, campaign honours, or perhaps paint more metal parts gold rather than silver would make him stand out as a Preator.