* How often do you see a team not sign their draft pick because the team didn't want to?
There are many reasons why this does not happen in the NFL.
1) If a team doesn't need a player that is available with their pick, there is almost ALWAYS a trade partner. Trading is almost non existent here. Which brings me to #2...
2) The draft really sucks here. Halfway through the second round there is little real value. The first and second rounds should be expected to produce quality starting players, the 3rd round should have cusp type players, and the 4th - 7th should have players who have a shot at making the majority of teams. Most of the guys in the 2nd and beyond have little chance of making 50% of the teams here, and you can find similar quality players in the free agent market. No one wants to make any trades (except BenS) because there is absolutely no value to any picks after the 2nd round... and the 2nd round is a gamble.
3) The way contracts work in real life is much different than here. Which means the cap is more useful. In 3-5 seasons, you'll see the result of all the 90% bonus money contracts, and it won't be good. Anyway, this affects a team's ability to be able to draft, sign, and try out some rookies. If the rookies were better, and the team's financial situations were more manageable, people would be willing to trade for these picks and try to get a boom player or just a quality backup and ST guy.
So, you can't trade your picks, and there are no worthwhile players available in the drafts, so you are stuck with your picks. So you have to take your picks, and release these players, creating a cap issue from the contract that you never wanted to give out. Eventually, this bad cycle will go around and around, and eventually create a very bad cap situation.
* A more problematic issue, let's say that someone takes over a team during early FA, then leaves. Maybe he was in a similar situation to BenS and only had 20-odd players on his team, so traded away a bunch of future picks for the current draft. Then, he decides to go awol and the AI drafts a roster full of good players. Those players never get signed, and his team is in even more dire straights than it was before.
This is NEVER going to happen. The draft is far too poor for it to happen. Plus, the AI isn't very good as far as drafting goes. But, let's go to your specific issue. AI should always sign the players... pretty simple and not even what was suggested. The suggestion is to allow GMs (real live humans) to have the choice to to sign or give up their rights to the player. If the team gives up its rights to the player, the player goes into the FA pool. Any player not signed by training camp goes into the FA pool.
5th round and beyond don't have any bonus, so they are easy to cut. The bonus decreases as you approach the 5th round, so the 4th round aren't terribly heavy either. I am more inclined to reduce the bonus (maybe 4th round and beyond don't get a bonus?) so you can cut those players without penalty.
We are just starting the 3rd round, and the highest rated non Kicker/Punter is a 63 future WR. Having played in all 6 leagues, I have come to consider the following:
90+ is a superstar
80+ is an above average starter
70+ is a starting quality player
60+ is a backup
Under 60 is, at best, a guy who is on the practice squad, and is always inactive. The guy you bring in when you have no other alternatives... a last resort. Not a guy worthy of being a pro, except on very bad teams looking for roster fillers.
We should not be out of backups and into roster fillers in the 3rd round. Now, check out the 2nd round... we had 10 players of 70-75 in the second round. 22 players drafted in the 2nd round are not even starting quality. This is the definition of a weak draft. It seems like all the drafts are this bad. In FOF, this would be a phenomenal draft. But it isn't FOF... the player pool is different here.
And this brings me to my final points. Everything is connected. One things affects many other things. It all starts, in my opinion, with the initial player file. Maybe the initial player file is too strong... but in all 6 leagues, what I posted above is about where players fall. So, strong initial player file, weak drafts, few human GMs, the trading system which is currently in place, the AI and signing bonuses, etc. etc. All these things interact. In the specific issue we are talking about here, you can't really compare real life NFL to this game... because sooooo many things are different. You have to take this as its own reality, and work with it based on that. In this case, because of the way everything else is, you either need to fix everything else, or allow teams a choice on whether or not to sign their draft picks.