That's a very good way to lose, very quickly.
Those four very good players aren't going to play every week, and unless they're RVP (14M for a reason) they're still going to come out of close to half their games with a measly two points.
Unless you're very good with your picks, most guys around the 4-4.5M range won't play regularly, and when they do play they won't score. A Crystal Palace centerback is pretty similar to not having a centerback at all in terms of how many point he'll bring in.
You really need 15 players who are going to be on the field for 2000 minutes or more a season. You don't need a backup goalkeeper if you're first choice is someone like Joe Heart (he's going to play every game and you'll never want to rotate him out) but the rest of the substitutes are important. The way the fixtures work, most teams will have weeks where they don't play (particularly the top teams) and you'll need to be able to rotate in cover who can be relied upon. Similarly there will be weeks when your Hull City centerback is defending against Chelsea, at which point having him off the pitch becomes something of a necessity.
I try to make sure that I have three solid players in each outfield position, and two cheap defenders and midfielders from lesser teams who I can rely on to play and who can be rotated in and out of the team as the fixture list demands.