Having a Suggestions thread in the Forums, means there is an arena-ful of players posting threads into it every day... Personally, I'd like to have an official list somewhere, that shows which Suggestions have been implemented(no credits) and also outlines what sorts of ideas OOO is looking to see.
Weapons, monsters, damages, status conditions, ect. There are no lack of ideas here, but, realistically, many aspects of the game are considered set in stone by OOO... Correct? I'm just as inclined to Suggest stuff as most other players who do, but I don't want to waste my time putting pitches together for things that probably aren't going to be expanded on in either the near or distant future...
Welcome to the Suggestions forums.
The Devs haven't replied here in like 8 months, so I doubt they'd take the time to make credits for anything here. I can tell you that the Missions system was from a player-suggestion..or many of them. Skold-The-Drac is the only one with a List of suggestions that are currently in progress; I highly doubt the Devs will copy that sort of idea, which is why Skold did it in the first place.
As for what they will/won't do, you won't know until you suggest it. In fact, you won't know unless it's implemented into the game. So, you're always taking shots in the dark.
SOME things have been said to NOT DO by OOO themselves, like Healing equipment and such, but there are not many of those. Typically, a specific idea must get a lot of attention before it is implemented.
~Sev