To be honest, if I was to describe (from memory, obv.) the London-brewed Guinness I wouldn't say it lacked body or freshness. It was a lot stiffer, with a bit of a darker, more roast flavour, and a creamy lasting head. The Irish version by comparison was a bit more 'wet', leaning more towards porter (while still absolutely in proper stout territory).
I found I enjoyed about two pints of the old London version and would then usually move on to something else, whereas the Dublin version you can just pour endlessly into your mouth. That's not to say I prefer the Dublin, they just had different uses for me.