This is my favorite graph for telling the story...
Players are very good at optimizing their returns if things aren't too noisy (too random). You can see that the more popular areas (larger bubbles) are almost exclusively the ones with the best leveling rate. Ideally, this would look more like a line than a triangle; that would indicate that our areas are well-balanced.
This graph clearly shows that the wyverns are easier to kill more quickly than any other spawns around that CR except for Xvarts, and that they are much more popular than any other spot on the map.
This should not be the case for well-balanced areas. If creature difficulty and spawn rates are evenly balanced for all CRs, this plot will look like a straight line. There are some RP areas which will have fewer spawns, and safe areas, which will have practically none, but the large circles should all form a relatively straight line. The fact that they don't tells us that the balance is off.
Smaller circles represent areas for which we have less data. The wyverns are so popular that other areas of similar difficulty do not have much combat data available. That means it's hard to tell how well-balanced those areas are.
In this update, scaling was disabled and some spawns were rebalanced. We hope that the result looks more like a line, but things are probably still not quite there, so it will require further work in the future. This doesn't mean we're "taking away good areas and making the game harder"; it means we're trying to do a consistency pass to keep everything in line.
The rate at which players gain levels and XP can be adjusted independently of any area. If we've balanced our areas properly, it's easier to control that. In the perfect case that all areas form a straight line with no gaps in it, we can easily increase the rate at which players level by tweaking the XP formula.
We can see the rate at which the server gains XP as a whole, and we can see the amount of combat that people in the server participate in. If players are earning less XP, that's something we can fix.
There is a risk/reward curve in BGTSCC. We don't force everyone to play content at the same difficulty. Instead, we scale rewards with content. Harder areas tend to give better rewards. It would feel wrong if you could kill chickens for 200xp each, even though that might get rid of an annoying grind for a lot of players who would rather just RP.
So when there is an area that sits above or below the risk/reward curve, we try to adjust it accordingly. If it's too much risk for too little reward, we might lower the risk, increase the reward, or do a little of both. When there's an area that gives too much of a reward for too little risk, that has to be adjusted too. Unfortunately, players get really attached to those areas; they plan around getting those rewards. So it hurts when that area goes back to where it belongs on the risk/reward curve.
This isn't a local vault server, and players don't appear at Lv30 with all the gear they want. There's progression. For many players who wish to make quick progress, there's a grind. I do not personally find this to be an attractive system; I prefer the local vault format where players can create their character at the power level they desire. However, the community seems to agree that we should have a progression system. (Not just the BGTSCC community; NWN/NWN2 servers appear to be longer-lived and more populous with server vault.)
So we have to balance our progression. If it's too steep, we'll run into the undesirable features of a local vault server. If it's too shallow, players will feel like they're being inadequately rewarded for their efforts. It's a delicate balance, and we're working to get it right.
Fixing the risk/reward of an area is not an indication that we are trying to slow progression. Those are things that can be adjusted independently. If areas are where they belong on the risk/reward curve, there won't be one grind spot for a given level; every area at that CR will be viable. We're not trying to screw you. We just want to give you options.