I always thought that Chase could have made an interesting subplot by having Silvio and Paulie fight for power. There was an interesting scene near the end of Season 4 where Paulie & Sil get into it in the back of Satriale's.

It's where Paulie was trying to get in good with Carmine and was horrified to learn that Carmine had no idea who Paulie was. Paulie was complaining to Silvio about Tony & Ralph. Silvio said that Paulie had been showing a bad attitude of late and, naturually, Paulie took offense. Paulie complained then about having to go to the Russian's house to collect for Silvio (Pine Barrens episode).

If they had started trying to make moves against one another, I think Silvio was better equipped to come out on top. Paulie had no stream of revenue like the Bing and was nowhere as near as creative to make money as Silvio. To top it off, Paulie was weighed down by having Christopher, who was mired in a heroin addiction at the time.