The NFL Competition Committee will consider a few changes this offseason, including the potential to increase in-season roster sizes from 53 players to 55. This would create 64 new jobs league-wide for players that would otherwise be cut, and while "two" sounds like a very small number for each team, the increase would make a substantial difference to front offices in trying to construct their roster. An added layer of depth at two key positions has the potential to be very impactful, especially at positions where injuries are common, like offensive and defensive line (and for the Seahawks right now, cornerback and safety).
Considering the likelihood that players 54 and 55 on any given roster would be at or near the league minimum for their pay bracket, the change wouldn't greatly affect an increasing salary cap (at best it would be about $1M extra to your cap, if you're talking about two rookies or first-contract players).
The Competition Committee is also considering the option of eliminating inactive lists for Thursday Night games. This would make all the sense in the world (inactive lists don't make a ton of sense to me anyway), as teams constantly scramble to field a competitive team after only four days of rest.
One additional change the Committee is considering relates to comp picks. The current rule in question states that any free agent signed after June 1st does not count against them in compensatory picks. This has meant that teams wait until after that date to sign veteran free agents. The proposal is to push this date back to May 1st, which would allow teams to start signing free agents earlier, giving them more time to acclimate to their new team and get involved with offseason activities.