Minecraft b5 in all honesty in just the best minecraft map(imo and i have not found a better one) and it could be argued that it plays a large role in attracting new players to the server, if new players looked at our server and saw some shitty minecraft map that that no one ever plays i doubt they would choose it over a server with minecraft b5, which of course would be a big issue.
Preference of a certain minecraft map is, what I believe, a personal opinion. sure, a lot of people may see Minecraft b5 as the best map to play on, but that doesn't take away the fact that playing the constant map over and over again becomes boring. I've played enough different TTT minecraft maps, and from my own personal experience I believe there are enough entertaining maps available to play.
I do agree that Server 1 should remain as it is now. It would be way too risky to drastically change server 1, as it could lead into gamebreaking bugs etc....
If we had had a 2nd server with a rotation of minecraft maps that do not require the CSS textures i think that could work, the only issue is that it takes time and effort to care for a server and currently as no one has time it would most likely end up dead just like the first server 2.
I know someone who was/is actually interested in managing a potential second TTT server. You know him as well.
Also there is the issue of staff, as many staff have been playing for a long time they could all flock to server 2 as it is new and has variety leaving server 1 with no staff, thus harming the original server.
It is likely that old players would like to return to Zarp, ones they have heard about the second server. In the short-term, the lack of staff members could form a problem. But in the long-term, I believe enough people will be interested to maintain the second server.
About the shift of staff from S1 to S2, I don't think this will form a big problem. The revival of server 2 will lead to an expansion in the staff team, as the level of interest in Zarp-TTT will certainly rise. In this way enough staff members will be active on both servers.