They say the battles are won in the trenches. If you have a dominant d-line it'll make it easier for the rest of the backfield. If you have a dominant O-line it provides more opportunities for the offense to flourish. Just look at the Super Bowl winners the last 20 years, they all had one or the other or even both.
On the contrary, look at the last decade. Our o-line and d-line have been pitiful, and we havent made the playoffs. Exhibit B would be Detroit; their o-line d-line finally started to gel and be great and they made the playoffs for the first time in a decade.
In conclusion, No, receiver is not an important need at the moment.