This is an interesting question and one probably answered by studying what meta is for PVP.
You have 3 considerations: raiding, combat and PVE.
Exiled Lands is rich in real estate and 2 things are pretty integral to it’s success for PVP: hidden locations and “meta” locations.
While it can be argued that there are no longer any hidden spots on EL since it is the oldest and most trodden map, not everyone knows every spot, so it can still be fresh. This would be an important feature for tactics, especially in retaining loot for smaller clans.
Meta spots in EL include mostly: keyhole, crevice, south aqueduct, gutter, watcher, docks, heliograph, various smaller caves and perma structures. The common denominator being protection of terrain or permanent buildings.
My thoughts on this are that if a clan has it, you have to be smart about removing them. Is the ability to build in these places a negative or a positive though?
So that brings me to Siptah. While yes there are protected locations, there are less. I can see where Funcom was trying to go with it: let people build with less protection. Quicker and easier raiding addressing many concerns about raiding over the years.
But I would argue that PVP on Siptah has not been as successful for that reason, not wholly as well.
So that now leads me into transportation. PVP is often thought of as quick and brutal. PVPing and raiding on Siptah has been painful. Everything hinges on time and resources. You have to have a horse, there are no maprooms/obelisks.
With the addition of sorcery we now have transportory stones and summoning circles. But, transportory stones have many caveats including the ability for opponents to activate and use them, so are carefully placed or not used at all.
Many prefer EL because of the ease of transport.
Now for combat. I wouldn’t really be concerned so much about space or design for combat as it ties so closely to raiding. Opposing clans will engage outside of raid hours, during while raiding or even 1 v 1 in their own fabricated arenas if they choose. It really depends on the social commonalities of any given server.
For gathering, I would treat it as PVE entirely because that is what it is. Think about what any player would want in terms of ease or trial of access to resources.
I’m one of those people that want all PVP servers to go back to x1 gathering and XP because I believe that one of the most successful aspects of PVP was the anticipation and planning required. Making things too easy can retain players with short attention spans but has broken much of what PVP was and not in a good way.
Tied in with pets, if you wanted a sabertooth you either had to brave the cold in Icespire or risk running into other players in Midnight grove. The bigger the prize, the harder it should be to acquire it.