The rest of this article will get down to the gritty details regarding minute changes, but if you're a hardcore Halo fan or had small gripes about the beta, this will be right up your alley.
The first alteration listed is a change to the voice that repeatedly yells "Flag taken" every time a flag is picked up in a Capture the Flag match. By the fall release, it won't be so overwhelming and repetitive. The same goes for all other voice callouts.
Several graphical fixes are in the works. The aiming reticules are apparently placeholder and will be easier to see come fall. Damage direction indicators are being adjusted. Several visual bugs such as "ghosting" have also already been resolved.
Gameplay changes are coming as well, some of them quite significant and others more minor. Melee smacks are being toned down a bit so that you can't throw two punches in such quick succession. Also, there will be fewer instances of players landing killing punches at the exact same time. The grenades are also being brought down a peg. Tweaks to everything from damage to splash radius to the number of grenades at spawn are being looked at.
The last little gameplay change mentioned is coming to the Stockpile game type, with adjustments being made to encourage a bit more teamwork.
For the full scoop on the fixes in the works, head to Bungie.net.