I'd have to disagree on several of these points. The proportions of the F-type aren't bad, but from anything other than directly side-on I feel like there's too much metal and not enough glass. High waists are in vogue these days but that doesn't necessarily make them ideal styling-wise.
I'd certainly disagree that it's rare for a sporty Jag to have great proportions. For one, the outgoing XK isn't at all dissimilar in profile to the XF - it just has slightly longer overhangs, which some may not be keen on but I think lends an air of elegance*. The previous XK even more so - it's now quite an underrated design, I reckon, with a lot of E-type to it in the coke-bottle lines:
(Spoiled slightly, I'll admit, by the rear bumper - a necessary evil unfortunately). The DB7 is similarly proportioned. Current Astons have made it look a bit outdated, but I don't think it's aged terribly - it's still pretty and now looks simple and unadorned. Spotted this one in the car park at Donington towards the end of last year - looked great in the metal:
And of course, the old XJR had absolutely fantastic proportions. Long, very low. Cigar-like form with a sleek glasshouse. Did the overhang thing just right, I think - you want a much shorter overhang at the front than you do at the back. It makes the car look like it's moving when it's standing still:
*
An essential Jaguar quality in my view. Jaguars should be graceful. Think tall, slim woman in a flowing dress, rather than a popstar in a short skirt.