Depends; if a series I love that is niche, such as say Starfox or Xenoblade, made it big in a way that retained the things I loved about it, then I'd be happy.
However, the risk here is that broadening an IP's reach to appeal to a mainstream audience often means dumbing it down for the masses, and in the process losing the qualities that make it great.
Regarding dev times, anything over 5 years is too much IMO.








