A good GM understands building a great team is about devolping a great core and then continually upgrading the pieces around that core to build depth. Right now we have Long, Bush, Hartline, Starks, Smith becoming FA in 2013. Those players are all part of the core that Ireland has established and appear to now be paying off. If he isn't able to resign them and still have $$$ left over to bring in players that either add to the core of the team and/or provide depth then Ireland is an epic fail.
Ultimately a GM is graded based on the team's record under his watch and right now to go from a 11-5 to 7-9 to 7-9 to 6-10 to 2-3 seasons make Ireland a below par GM.
If that was true he would have been fired with Sparano. Records are more on the coach. Ireland doesn't call plays. Ross felt the Dolphins had talent, but Sparano wasn't developing it. So far Philbin is proving him right.