Not quite sure what you mean by "hard magic" systems -- given that we're working with the HERO system, I suspect that it will be much more efficient for PC spellcasters to build their characters using VPP's or other Power Frameworks rather than buying each spell as individual powers; but I'd want everything statted out and GM-approved in advance, and only the most powerful wizards would be able to make up new spells on the fly in a combat situation. New spells would have to be learned either by training with other casters, or laborious research and experimentation undertaken during the PC's down time.
As to the setting? I want to steer away from things that are too predictable and familiar -- I want exploration and discovery of the world the PC's are in to play as much of a part of the campaign as defeating bad guys. I think that's part of the appeal of the Numenera setting to me -- with the world being so old and influenced by so many different sources and races, pretty much everything is up for grabs, and the stories are limited only by the imaginations of the players and GM. I've also heard good things about "Skyrealms of Jorune" for creating a fantasy setting with truly alien elements, although I'd need to do some serious boning-up on the setting before I'd feel comfortable adapting it to HERO.
Another idea that comes to mind for a "fantasy plus" setting -- something an old friend in Maryland and I had kicked around back in the day -- would be a game based on (or inspired by) the 80's cartoon series "Thundarr The Barbarian". For those unfamiliar with the show, here's the "elevator pitch":
The original show was a mix of "Conan The Barbarian", "John Carter of Mars", and "Star Wars" -- there's very clear delineations between the "white hats" and "black hats", wizards and possessors of "super-science" tech are generally evil and have enslaved the local populations to create their own little fiefdoms, and selflessness & heroism will generally win the day against the forces of evil. For an RPG I'd want to make things a little more nuanced, with more shades of grey; just how much would depend on what sort of a campaign the players are interested in...