It's really nice to see such a discussion going on in a civil, honest way, back in the day there would be too many "but ur playin a monster race!" shouts in such thread. Thankfully the culture changed and so I think it could be a good time for ruling changes too to represent it.
The UD always had unstable population, jumping from full stagnation to high levels of activity in months. Making it active is totally possible, but it takes at least 2 really dedicated UD players who generate RP wherever they walk (like it always was). Cross-realms restrictions are clearly a huge reason why. Formally these restrictions penalize both realms equally, in reality they always punish the UD in the first place. You can't properly immerse with the dangers of the UD because you, as a player, feel that the UD is a way safer space than the surface. Liberal Sshamath against xenophobic authoritarian BG, wildwest surface North vs quiet road to Sshamath without a single KoS zone on its way, the real server experience doesn't fit the narrative we're supposed to believe.
I do have a set of things that would help with the situation. They're not new, I voiced them many times in similar threads in the past, here they are:
1)
KoS. It's a topic of its own to explain why this mechanic is obsolette and brings nothing to RP environment. Instead of completely deleting it, it's fine to rewrite it to something like normal PvP rules, but more harsh. A great (and recent) example of this is
the new PvP ruling by the DM team, regarding shapechange:
- While polymorphed into a form that is not your own, you are perceived as being what you have become.
If your PC has taken the form of a Race/Monster, they are considered to be a creature of that form, in-character. While you remain in this form, it means that you accept that your PC may be set to hostile by the other players who see you, and that you agree to any hostilie Role-played towards you, or even being attacked, for as long as you remain in that form. Remaining in monstrous forms after being shown in-character hostility and being set to hostile, is considered consent to actual PvP attack. Changing into a non-threatening form, or returning to your natural form again, removes this consent.
This ruling has spirit of KoS, yet it's pro-RP and is respectful to both parties of the conflict. Its implementation went well, so I think it would be great to extend a similar ruling to the UD / Surface CvC interactions.
2)
Loot restrictions. The same as with KoS, rather than completely lifting them, I suggest expanding the neutral zone from the Upperdark to the surface North, including areas such as Forest of Wyrms, Highmoor, Boareskyr Bridge, Fort Prominence, Thundar's Ride, Troll Claws, Winding Water and some others. In these areas, penitentiary rulings don't work and UD'ers can freely loot. This suggestion will give a lot of air to the UD community, and asking "what is the RP reason drow loot on the surface?" shouldn't even be a question, because the answer is the same as what the surface adventurers are doing in the deep dangerous caves. They're adventuring.
3)
Crossrealm squatting. Underdark characters who wish to squat on the surface, to live on the surfacers, shouldn't be legally penalized for doing it, this activity should remain strictly within the RP field (unless there's some player conflicts caused by this RP that need DM intervention). The same, of course, goes for surfacers squatting in the UD, but I've noticed that the latter have way more freedom in doing so, up to limitless stay.
These three suggestions would greatly improve the server experience and make the UD character gameplay more enjoyable. As for making the UD more dangerous and less accessible, well, I agree the UD is way too softcore (even compared to the local surface), but you can't just make the playerbase believe it's super distant and dangerous while it takes 3 minutes of walk to get to Soubar from Sshamath. Add more high CR zones between the Titanfist and Ogre caves, this is probably the most sensible solution (Although it takes area builder time).
As for the fear of PvP mongering, aka a very mechanically skilled drow player playing solely for baiting surfacers into PvP, these situations are quite rare these days (and not because of the restrictions, but because of the current server culture). If they arise, deal with them individually, I'm not the first to say that there's 0 reason to punish the whole community due to 1 bad apple.
Lastly, my suggestions are not a panacea for all possible UD-related issues, and some of them are so fundamental that it's impossible to resolve (such as the depressive cave atmosphere of the UD setting), yet these are the steps to the right direction. In the end, there's no actual realms, we're playing on the same server and it's time to acknowledge it.