We do need more talent - especially in the spine (as many have pointed out), but I think the bigger issue is that we can't rely on big signings to come in and improve this team.
We need to improve the team as a whole - improve the systems, the structure we play with, the strategies the squad understands and implements effectively. Even good players look like rubbish in a team which lacks structure and cohesiveness, and on the flip side, average players not only look good but also develop into great players by being elevated by the play of those around them and the success of the team system.
We could sign Ponga tomorrow, but he cannot change the trajectory of this team alone. All 13 players on the field have to be doing their part and working together to guarantee success and while elite spine players may cover for a lot of deficiencies, there's others that they cannot.
The disparity in talent across the teams isn't nearly as big as many believe - it's about putting what talent you have in a position to succeed and creating an effective team system / dynamic. There's a reason the Storm and Roosters can pick up off-casts from other teams (Brenko Lee, Morris twins etc etc) and they look instantly better than previously - it's not that their squad has more talent, it's just they're putting their players in a position to use their talent to benefit the team.
I honestly believe we need a new coach who can achieve this far more desperately than we need any more marquee signings.