Personally, I hate this forum. It's such a time sink, everyone I know has accused me of "wasting time". Well, excuse me, mom and dad, my forum replies and messages aren't going to read themselves. I also have games here, somewhere, I think. Anyway, I would be happy if this forum becomes so dysfunctional that it implodes unto itself, and when it's no more, I will finally get up, shower, and get something to eat.

Also, remove the downvotes, yo; upreps cool.

From the top of my head:

-- A functioning search system (I believe there's no need to explain further).
-- The ability to check my own post history at least.
-- An ignore posts/ users feature.
-- Add last poster column to threads list.

-- Add the extremely useful forum-related features from Barefoot_Monkey's userscript.

-- Restrict the privilege of PMs only to GOG staffers for banned accounts.

May edit in more later.

EDIT: Added a few more suggestions, may not be the last ones.

Not sure if PMs fall into the this subject, but some more functionality to the PM system would also be greatly appreciated.

EDIT2: In light of a recent scam of three people in The Classifieds thread (posts #10655, #10657, #10659 and #10683) and given that banned accounts can still use the PM system, I'd like to put in a request to strip banned accounts from the privilege of PM-ing others.
EDIT2-1: Added one more report on being scammed by the same user "The_maestro27".

EDIT3:
- Organise the forum of each game series into sub-fora, one for each title, as searching for threads related to a specific title from a series is currently a pain in the butt.

There should only be positive rep. Negative rep is dumb and subjective. Keep the plus button and timeframe rep bonuses and eliminate negative rep entirely.

General discussion should be split into general gaming and general off-topic.

All gift and giveaway threads should be condensed into one giveaway thread stickied at the top of the forum.

Poll function should be added.

I would also be down for a good search system and the ability to look at my previous posts.

Edit: Merge the Alone in the Dark forum with the Alone in the Dark: The New Nightmare forum.

I have found myself searching for hours trying to find specific posts by other users or even posts I've written myself. Posts that I like or found useful. The search function doesn't help much.
It would also be a good way to avoid shady people on classifieds or giveaway threads.
And while we're at it, a better search would be great too. :)

1. Better search function

2. Ignore user option

3. Ability for the OP to close/delete a thread s/he has created

I see two possible ways to keep the rep system while improving it.

1. Remove downrep, keep uprep.
Pros: Constructive members of the community will still be "rewarded" for their efforts, and there will be no downrep system for people to abuse.
Cons: There will be no way to downrep those who truly do deserve it.

2. Keep both, but make all upreps and downreps public.
Pros: Letting everyone see who downrepped a post means no more anonymous downrepping. When people can't hide behind the anonymity of the downrep button, the number of downreps should drop dramatically.
Cons: Letting people see exactly who has downrepped what could spark off new conflicts and rep wars.

Also, as DarkoD13 says, post history would be an excellent addition. Every other forum has it already. So would yours, if you didn't insist on coding everything yourselves ;-)

Overall, I'm happy with my experience with the forums, but, then again, I don't extensively use all of their functionalities.

The one thing I think needs immediate improvement, in my opinion, is the search function, it's not really fleshed-out and leaves a lot to be desired, it fails to find topics that I eventually find manually.

I think an option to keep track of all our posts automatically, without having to favourite a thread or limiting them to a time period, as it stands now, would be a nice addition.

As for the reputation system... I'm of two minds about it. I don't think getting entirely rid of it is the way to go, but maybe we could reach some common ground regarding this issue? I, for one, like the ability to uprep users, it's a way to say thanks when they are really helpful and/or provide me with insightful and pertinent information. Or, well, when they are just fun to be around! But the downrepping has been largely abused, and I honestly think that should go. Maybe restrict it to moderators, or create a system in which whenever a user gets reported and proven guilty, then they get downrepped? I honestly never downrepped anyone, if I disagree with them, then I speak my mind, but downrepping sounds absolutely stupid to me, it's just a way to punish people just because we think differently.

Just my two euro cents. Which, in Portugal, is a very ugly coin.

I would like to see this feature. I would be nice to easily relocate posts/questions/etc that I have made.

Nobody would have anyone to posts to. :P

For the purpose of the rep discussion, an easy way to see the post history of another user would make it a lot easier to see if he/she is generally obnoxious or you just caught them on a bad day.

While I don't think the search is as horrible as others seem to think, I do think it would benefit of having the ability to sort by date rather than relevance (which I guess it's using now), as well as options for searching only within posts, only in thread titles, or the current both.

Personally I do not see the need for an ignore function, but I do realise there are several people who do (I even coded a user script for that function long ago only to see if I could, because someone else wanted it, site updates have since broken it though).

Also, yes, seeing my own post history.

GOGmixes likely fall outside the forum, but I'd like the "my gogmixes" page back.