Many aircraft will struggle and be close to the limit of their capability.
The idea of aerobatics, to an extent, is that you're going to fly the aircraft to the limits of its capability. So that the aircraft will struggle (or downright fail) to perform some maneuvers is a given.
However, some aircraft have far wider limits than others, so it will take a lot more effort, training and g-tolerance to get to those limits.
And let's be honest, flying an R2160 to the limits of its (meagre) capabilities can be almost as rewarding as flying an E300 to its limits. Not quite, but almost...
