BMC / BL would have not been unique in investigating an evolutionary approach to replacing successful cars with updated versions remedying various flaws of the originals, both Volkswagen and Citroen were tempted as well for icons like the Beetle and 2CV respectively. Ford and other carmakers managed to do well by adopting an evolutionary approach to replacing their cars, the Cortina up to the mk5 and possibly even the related Sierra come to mind.
Volkswagen Beetle
1) https://jalopnik.com...-lat-1818581916 (albeit more a what-if)
2) https://jalopnik.com...n-ne-1792130876
Citroen 2CV
1) http://www.citroenet...v/2cvretro.html
2) http://www.citroenet.../2cv-hayon.html
As for an updated Mini. Would say Project Ant is a decent starting point (albeit minus the external seams), combined with the costing of the production ADO20 mk3 / Clubman (including realization of projects mentioned in pages 144-145 and page 151 of Mini: The Definitive History) and the slight length / width increase of Minki-2, mainly under the rationale of comfortably fitting an end-on gearbox to an A-Series / A-OHC unit as well as allowing future scope for a new engine to be fitted (since the A-Series was still slightly smaller then the K-Series and thus an A-Series with end-on gearbox from a Maestro would have easily slotted into Minki-II sized car despite being a tight fit in the original Minki project that retained the original Mini's dimensions).
New features for the updated Mini being 12-inch wheels, hatchback (including 5-door), wraparound bumpers, coil-spring or (R6-style) Hydragas suspension, front-mounted radiator, electric fan, oil cooler, a comprehensively engineered sound-deadening package (an alternate early version of the real-life 1980 “Quiet Mini” package albeit uncompromised by accountants), internal bonnet release and a 5-speed gearbox (or 4-speed gearbox with overdrive) or if still making do with in-sump gearbox layout a production version of the 5-speed AP Automatic transmission developed by Keith Gerrard of Bushey Transmissions in conjunction with Jack Knight.
In terms of styling, while it is a subjective thing there was choice of roughly three options available. The first being an Evolution of the Classic Mini (aka Project Ant), Modern (Clubman including hatchback) and Bertone (Innocenti Mini).
Am sure there are other as yet unmentioned potentially useful or viable updates or styling options that were investigated for the Mini.
Edited by Mite, 31 October 2018 - 06:26 PM.