Remember what we talked about in that thread about Brazil? Change the WI and have Pombal survive. Would he influence Maria to move her court to Brazil? Did he have any influence on her to begin with? If the move happens, keep in mind that the colonial capital of Brazil at that time was Bahia (Salvador); Rio de Janeiro would take its place in 1763 in OTL.
How would this influence the territorial disputes with Spain in South America? If the clash with Spain during the 7 Years' War still happens could it lead to a weaker defense of (European) Portugal?
Well, Maria didn't like Pombal, one her first actions as queen IOTL was to dismiss him. Of course, the origin of her hatred towards Pombal was the Távoras' Affair, which happened after the POD, but I think that she was already deeply religious enough in 1755 to dislike Pombal's modern views. IOTL she didn't want to go to Brazil in 1807, but at that time she was old and insane. But now she would be young and still healthy, I think that she wouldn't accept.
But, if somehow they had made it, and the Seven Years War still happens in the schedule, then that would probably be a tragedy. Portugal would need to be neutral or would suffer a lot. IOTL the Spanish invaded the territories North of the Douro River, and in South America large parts of the capitaincy of Rio Grande do Sul were occupied. Now if you add to this equation a court that fled from Portugal when the country needed leadership it doesn't soud good.