But every creator, whether they be on an A-list, B-List, or C-List character generally tries to build similar foundations for the title their on even if they're book will only last for 6-16 issues.
Nightwing is probably in a better position then most characters because he can actually hold a solo book, so it's easier to build or maintain a foundation unless future writers just completely do their own thing once they take over. But that happens even to more secure A-list characters.
I'm not the biggest fan of that fluidity myself, but to each their own.Also arcs today rarely are "one-offs". They tend to last for multiple issues, and you aren't really just throwing out a villain from a different franchise for an issue or two, but would be building an entire arc around that villain and story. Though I suppose it is also a difference in philosophy. DC tends to keep its properties very segmented while Marvel feels a lot more fluid where its characters dip in and out of franchises and move around the MCU fighting villains and problems all over the place.