I'm conflicted between the medieval server and resident evil. Now, when it comes to the medieval server, there's already one that was made and seems to do pretty well. We wouldn't be able to stand up against it.
Now, onto the Resident Evil server proposal. It'll be something unique and new to G-mod as there is no RP server based around Resident Evil. Yes, there are zombieRP servers but they don't have much of a lore behind them. When it comes to Resident Evil, there's a ton of lore that we could work upon. On top of that, the server will run rather well as the RE2 remake just came out and did pretty well in its sales.
I can see the lore the server running on being based around a certain spot within the Resident Evil time-line. Just like Kai suggested, when it comes to making a decent profit, S.T.A.R.S, tyrants and even some of the zombies can be used in order to get that profit. On top of that, events for Resident Evil could be interesting and unique. Again, the events would have to be based around the time-line the server was set upon. Let's say the server was set during the time of RE2, be it in the beginning or middle of it. The event could be based around the idea of the G-virus spreading due to Umbrella members shooting down William Birkin. If it was based around the middle of the time-line, the event could be based on preparing for either a massive growing horde of zombies attacking the city or a few tyrants being sent out by Umbrella to see how they're used in combat against armed personnel.
Now then, if the server was decided to be based around Resident Evil 1, that would be more unique. During the time of Resident Evil 1, there wasn't much known about what was causing the outbreak in the near-by town. It could be a mystery that the survivors would slowly have to figure out and form small groups in order to survive against the growing zombie numbers. An event idea for if the server is based around the Resident Evil 1 timeline: after running out of food, the survivors would have to head into the woods and find another mansion. They would have to search for food, fight off whatever is inside and figure out what caused the out-break with little notes left behind by researchers that either died or became zombies due to the T-virus.
So... yeah. I gave my reasons as to why a Resident Evil RP server is a good idea and I hope it helps out with what server is going to be made next.