Interiors on those XJs was definitely an improvement over the previous generation, and yes, I would expect the design would still feel distinctive just two years in. But at some point, I feel like design in the industry evolved in the same direction, and the XJ didn't look 'different' any more.
I also agree that Jag should have left SUVs to LR and focused on niche segments, as you mention. Then again, when even Rolls-Royce, Lamborghini, and bloody
Ferrari start building goddamned SUVs, it's hard to say "We'll pass." Hell, even Lotus and McLaren have SUV models in the works.
LOTUS! The brand whose founder's key design principle was 'simplify, and add lightness'.