I'd go in the completely opposite direction. Lighter, simpler and less GT like. There are already plenty of overweight convertibles with good torque, more displacement and lots of gadgets (Z4, 350Z come to mind). If you want a retractable hardtop, there's a Pontiac or Lexus dealer down the road. I say more carbon fiber, aluminum, composite and titanium components. Lighter weight wheels, upgraded brakes. But, keep the compact I4 and ultra-smooth tranny where it is. Updating the valvetrain to i-VTEC would be a nice change if it doesn't sacrifice space or weight. I'd be willing to accept side airbags and a dual stage passenger bag if they didn't add a ton more weight.
In other words, make it more Elise like but with Honda reliability and price. I don't want the car to have mass apeal, but my goal isn't to sell cars, it's to have a unique product that appeals to a very select demographic that likes to DRIVE cars.
Definitely keep the current simple product line. There should be no separate TypeR-specV-Track version or any of that nonesense.
Every car that rolls off the line should be the Track version. When you see another one, you want to be able to nod knowingly that it's the same car.
Design-wise, it should remain an adult car. No stupid wing, no holes or ducts that don't go anywhere, no decals that say DOHC VTEC or any of that ricer crap. In fact if Honda wanted to stay with just a "H" emblem that would be perfect. If it has a hoodscoop it better be functional in some way. Roadster styling with the long nose, engine over the front wheels. I personally like the 'deep' seating position in the S, unlike the Miata or Z4 where the doors are a bit below your armpits. Could do with less wheelgap, but not at the expense of less suspension travel. Could lose the fake dual exhausts (it is an I4 after all with only a single manifold), but I could live with them if they went Ti for some weight saving. A single exhaust that exits in the center (Boxster style) still has the nice symmetry of a dual without he fake styling. Dual HID (low and high beam), full LED tails (turns, backup lights too) to bring lighting up to date. Definitely keep the F1 style instrument cluster, it is a major space saver and I love hearing losers that have never driven an S2000 'complain' that a digital dash is so 80s
