Sadly it's pretty much too little, too late for a lot of folks who won't bother.
I finished the game, or rather I stopped playing during the finale sequence:
Spoiler for Hiden:
In one of the last missions, you go to a landing zone to get a dropped briefcase. The moment you pick it up, scores of enemies spawn all around you. That's bad enough. But I couldn't kill them! Not on hardcore. So I changed the difficulty to "easy", but they were still almost impossible to kill and I'd get nailed every time. I finally went to the guide which noted that in this mission the bad guys are significantly harder to kill than elsewhere in the game

. I decided enough was enough, even though I was probably one or two missions from completing the game.
Perhaps the second-most interesting tweak is the ability to play ranked matches on user-made maps. "You should already find a selection of those maps thanks to some of our active community members," the team said.
I never have gotten into multiplayer, it just didn't seem to appeal to me. Maybe this change will motivate me to try again.
Meanwhile, the new patch also fixes a few random bugs in single-player and multiplayer, and introduces a new "hardcore" damage model where all weapons do "much more damage".
Hmm, a damage model that increases vulnerability? This might be worth checking out if it makes hardcore mode more like CoD:WaW hardcore. Mind you, it might make it impossible for me to get too far into the game, but it does have an appeal if it applies equally to the AI characters. In the present game they would go down with a single sniper shot (mostly), but often I could put a half clip from an assault rifle into them and they'd just stagger around and then resume firing. I wouldn't mind my character in the game being more sensitive to damage as long as the AI is equally as vulnerable.
UPDATE: Here's the text of the update info, from the Far Cry 2 forum:
Today we are pleased to announce the release of a Farcry 2 title update for Xbox 360.
This patch will include a lot of improvements for both single player and multiplayer modes; with better browsing features, more multiplayer game options, and other new additions in order to let you play the game, the way you want. Information on a similar update for PS3 and PC will be announced soon. Here is a list of the fixes and additions:
Single Player
Fix some random crash occurring during specific Malaria attacks
Fix health damage not following the difficulty level when switching difficulty during player’s walkthrough
Fix some camera issue when using a mortar near a rock
Reduce significantly the probability of having a corrupted save game*
Multiplayer
Add Respawning time in Host - Advanced options - player match
Add Starting rank in Host - Advanced options - player match
Add min players in the host option
Add deaths in scoreboard
Balance current damage model
Show VIP on Scoreboard (for your team only)
Players can stay on the same host for consecutive matches in Ranked match
Add a Quick match button when selecting a map in the Map community
Fix vehicles spawning on their initial position immediately after being destroyed by an explosion
Fix client being disconnected from the host randomly and not being able to see it after that
Fix death message does not appear randomly
Fix some issues when interacting with objects
Fix bandolier doesn’t always unlock extra ammo
Fix some bug when healing another player and getting wounded at the same time
Fix diamond gain in rank mode
Fix players don’t get a request to keep a map after playing on a IGE map
DLC Fix some issues when using the crossbow
Extra features
Add a “hardcore mode” that will provide a new damage model where all weapons do much more damage to increase realism.
Add the possibility to play Rank matches on a selection of user maps**
Many of the new features were requested by members of the community and we would like to thanks everyone for taking the time to communicate with us, we hope you will enjoy the improvements.
* We are very aware of the problems some people have been experiencing and have been doing everything within our powers to resolve these issues as quickly as possible. We found out during our testing that several elements could cause an issue with the same consequences and therefore prevent certain players to finish the game. We have been able to provide solutions that prevent those corruption problems in most cases and we haven’t encountered any problems now. We apologize wholeheartedly for the inconvenience that this matter has caused to some owners of the game.
** In answer to a growing demand we have developed a tool that enable us to mark user’s created maps as ranked. You should already find a selection of those maps thanks to some of our active community members.