I agree that the David West situation is worse than the Kevin Durant one. I don't really begrudge the Warriors getting Durant - they did it under the salary rules while paying a fair (in fact I believe max) contract. In Miami, LeBron/Wade/Bosh had slightly sub-max contracts to make it all work if I recall correctly, but they weren't being paid at something far below market value.
West, on the other hand, would have been worth $10M easily in this market and by signing for the minimum (for the second year in a row, no less) he is effectively giving the Warriors an extra $8M+ in salary cap space.
I'm not sure that the suggestion that you've made will actually do much. Even if the Warriors had enough players to force West to sign for a "graduated" minimum, would this make any difference? If the graduated minimum was still an exception, does it matter? It's not so much that the Warriors aren't paying full price for West - I'm sure they could afford it - it's that they're getting a subsidy on their salary cap number allowing an even greater concentration of talent. I suppose that if a team were to clear out their roster in order to sign say three players to large/max contracts the roster charges for the graduated minimum (as opposed to the veteran's minimum) would reduce the total amount of cap space they had, but that wouldn't actually affect the minimum players like West. Who slides into which slot isn't going to make a lot of difference.
I think the way to solve problems like David West is to prevent players from signing ridiculously under-market contracts. That's not easy to do, but I've got a simple suggestion that might work: a free agent auction.
Now, normally free agents would not go to "auction", but imagine this: When a player signs a FA contract for less than half of the maximum, there would be a short period, say 24 hours, during which any team could call an auction - and by calling the auction that team automatically opens the bidding at 2x the signed contract. All teams with sufficient cap space may compete in the auction, and whoever wins it gets the player. I'm betting dollars to donuts that at least 15 teams would have gladly doubled West's vet minimum deal. Because the threshold is 2x, and because the team calling the auction would be forced to open the bid, I don't think you'd get frivolous auctions. ("What? Afflalo got $12M? No way, man, we're going $24M!" Not gonna happen.) And the simple threat of it would prevent a guy like West signing with the Warriors for the min, because he'd know that somebody would overbid them and then he would have no control over where he went. In fact, if an auction provision were established, it still might never be used - the threat of it would be enough to keep guys from signing contracts hugely under market. Obviously 2x is just a starting idea - maybe 2.5 is better, maybe 1.75 is better, but the concept is the point, and I think it would go a long way towards forcing the super teams to have "reasonable" benches that don't violate the spirit of the cap rules to concentrate talent.