I've given my opinion on this already, instead of copying the whole long ass thing, I'll just provide a link for anyone interested in it.
http://www.sourceop.com/modules.php?name...=7715#7715
I think it ultimately depends on how you want to view the donations DF. If you rely on the donations to keep the servers up, I certainly would increase the number of slots and/or make it a monthly donation of a decent amount. I'm not sure of the costs of the reserve slot, but from what I understand, a mere $10 is enough to get one. $10 once, for a 'life time' reserved slot is very, very generous.
If the intent of the reserve slot is just to say 'hey, thanks' then ... I honestly don't know that I would change it.
The Valve server is definitely getting more popular. I see a lot of 'new regulars' (I guess you could call em, though they are on more often than I am now, I'm sure) than in the past playing there. Even if the intent of the reserved slots was a 'thank you', it doesn't mean the situation can't change.
I haven't spoken very much, if at all, to you DF so this is just me grasping at straws. It feels like the intent was to toss up a donation option and offer a reserved slot to see if people would respond to it. Perhaps you didn't expect the response that happened? I feel like maybe you feel like you are between a rock and a hard place. You feel a responsibility to the people who donated to get them on the server, yet you also want to keep the public streaming into your server. I don't think you can please every one in this instance, to be honest. Some will feel like you are catering to the donators and will harbor jealousy/animosity towards them and others will feel like their money wasn't worth what they thought it was worth when they gave it to you and feel 'cheated'. I really think you need to come to a stance on the subject though and one side is going to just have to accept it. Increase the number of slots to 32 and tell people if they are tired of getting kicked, to donate and change it to a monthly fee. Or, tell the donators that having that many slots was never the intent of donating and keep the slots at 12, possibly 16 and I guess apologies for any misunderstandings. I would update your donations page to reflect either decision though - so people know exactly what the donation is there for.
As some one who has been in a few online communities, I can guarantee you, as soon as you begin to restrict and limit the amount of new, public players, the quicker the 'community' will stagnate and die out. It is ultimately to fate of every community unfortunately. People move on and get interested in other things. But without new players and 'new blood' to the server, there is, in the end, nothing to replace the players that have moved on. If that point comes and the server is again open, or more open, to the public - people may not be as attracted to it as they once were. Perhaps even hold a grudge against the server and/or it's regulars.
I always mean to start out my posts keeping to the points as well as I can and to keep it short, but it always ends up as a novel. I'm sorry to anyone this annoys, I guess I feel like I have a lot to say.
/shrug