I wouldnt get too worked up over it. Its not like some small microbrewery changing the formula of a handmade cult classic or something...

Guinness' forumula is far from sacred. The nigerian version of it, which is sold as an import in Europe actually tastes better than the standard verson - and is made from Sorghum! Moreover Guinness itself is a very industrialised beer, full of additives and preservatives anyway. Nor is it all that thick. For a stout it is actually relatively swatery and lacking in flavor.

Frankly in my time in Dublin I found the stouts from the Porterhouse far more interesting than the Guinness. in that town.