Alex - you should get a job on the design team
Unfortunately I can't draw for toffee
I tried making a few sketches to back up my statements, but they were too bad to show.
Basically, think of an Uno, then stretch it a little in length and width, and fit big wheels. Keep the flat-ish sides with three creases - take one of the creases right around the car (except where the wheels are, obviously) and make it part of the shape of the lights. Keep the windows large and the windscreen large and curved, seating position fairly upright to give a good view out. The bonnet should be drawn tight over the front wheels yet fairly long to give a proper car-like profile (not short like the smallest hatchbacks - C1, Smart car - use the space behind the engine for a proper heating/air conditioning system) and the headlights should be straight across with the grille, low as possible. The car you get looks quite different to modern shapes - flatter panels give a more practical shape, but straight crease lines should break it up and the large windows will prevent it looking like a van. A larger car (compared to the original Uno) should drive well - wide track should help. I always felt the Tipo drove like a more modern Uno.
I wonder if anyone has thought of a brainstorm session to pick out the best attributes of the Uno. It seems like most were lost in subsequent models. I've mentioned the seats and dashboard, but there are many more (the rear quarter windows on 5-drs, for example, not present on the Mk2 Punto). The spare wheel under the bonnet (of Brazilian versions) is an old FIAT trick that should be revived now that engines are smaller
Have you ever noticed how you can fit a coffee table or a washing machine in the back of an Uno, yet you can't fit the same into the larger, newer hatchbacks such as the Punto or Stilo due to the shape of the opening and the supports at the sides that make it hard to even remove the shelf. This sort of utility is always appreciated - I think FIAT should make a car that is genuinely useful as a family 'van' yet still car-shaped and pleasing to the eye. Basically, a large hatchback, like the Tipo was. FIAT could boast that the new Uno offers more cargo space than a Range Rover, yet more seating space than a BMW 3-series. Or something.
A new Uno could preserve the neatness of the original design, but slot into the range above the Panda and below the Bravo (I think the Bravo is just about forgotten anyway - that looked like a blown-up Grande Punto to me).
That proposal to make the Uno smaller than the Grande Punto - better - but I can't say I agree, though it's a reasonable design, it just looks too feminine for me. Small and curvy, like something from Korea. Surely the 500 already fills this market niche and looks more characterful. What would the five-door Uno look like? Notice how the short bonnet is so far above the front wheels and notice how small the wheels are, nothing like what I had in mind. Good packaging, maybe, but an elegant shape that anyone would want to drive? Dunno...
When the Uno came out, with its crisp simplicity, smooth and gutsy engines, and functional yet stylish interior, it instantly made most of what was on the market look staid and old-fashioned and the ride was so much less lumpy than most small cars. I think, to do the same again, the Uno needs to be a technically-clever car capable of matching the speed and handling of, say, a BMW 3-series, yet in hatchback form. It needs to reach above its market segment in driveability and (of course) there needs to be a hot Turbo version as well. I don't think a small, cute body on the Punto platform can do that. They should instead use the Alfa 159 platform but with 5-cylinder engines (petrol and diesel) and the bold, flat-surfaces hatchback shape I described. Then we would have a hatchback with nice handling and performance - something to make a Golf look bloated and slow
Maybe a way to achieve this would be to start with the current Lancia Delta, and square off some of the surfaces, fit a more utilitarian interior, lose the chrome and luxury. FIAT Group has so many cars at its disposal to choose from!
-Alex