Yes, there were a lot of little "Kingmakers" scurrying around trying to change the succession. The interesting thing is that the biggest problem in the eyes of the establishment was that Bertie's heir was a woman, not that he was delicate, or stammered.
Good grief, there were even machinations to bring back good old Uncle David as Regent when George VI died as certain "gentlemen of government" sought to delay the "heavy load on such a young woman's shoulders".
Honestly, it makes me wonder however we ever ended up with an Elizabethan and Victorian Age. It would seem that back then they had more respect for the succession so they either thought they could manipulate the monarch or arranged their death or that of the heir, etc.
I'm not sure I'd agree - I think it's actually surprising that we did end up with an Elizabethan and a Victorian Age. The respect for the succession was no more existent then than it was during the abdication crisis.
At the death of Henry I, the lords had so much respect for the succession that they ignored Henry's heir, Mathilda, and put her cousin, Stephen, on the throne causing a lengthy civil war.
At the death of Edward VI they had so much respect for the succession (as dictated by the will of Henry VIII) that they tried to bypass Edward's half-sisters, Mary and Elizabeth, in favour of his cousin Jane (the will itself bypassed the descendants of Henry VIII's elder sister, Margaret, in favour of those of his younger sister, Mary).
During the reign of William IV it was suggested that heir presumptive Victoria be passed over on the grounds of her age and gender; it was even rumoured that William's brother, Ernest Augustus, was plotting to murder Victoria. Even those that accepted Victoria as future Queen were concerned about her age and possible regent.
Pretty much every time the heir has been young, female, or both, there have been succession debates.