I'm never going to forget how giddily happy I was to see Mac back, scrapping it out with calibre and acting more like the character we saw in the old X-Men issues.
Getting back on topic: I agree there's story potential in Calibre, even if that's only because he's shown precious little before. He's mostly a blank slate. A goofball in armour with a big attitude. He doesn't seem the type to have created the tech himself, so that leaves us wondering where he got it -- and the story behind that alone has great potential.
What if it's the Master at work? Manipulating some socially-misaligned individual into wreaking havok at strategic times and places with technology that the Master considers inferior, while the rest of the world views it as high tech? Disguising his movements behind the scenes. A shoot up here, an explosion there: change real estate values, alter the net worth of companies, change public perception of certain regions, foster fear in the right time and the right place -- all in a game of grand manipulation behind the scenes. Have him be a
true evil genius, manipulating society on many levels, accruing power in many forms, making him a genuine threat instead of just some bearded nutjob in dancing tights with an over-powered sentient tinkertoy at his disposal.
Some folks may have guessed that the ideas above aren't so off-the-cuff as they might seem.