"Also we've got Sleepwalker and Stygian as new maps. Sleepwalker is a fairly small desert map, whilst Stygian is a misty mountain map. Both of these seem suited to deathmatch, so we've decided to keep these as maps for our TDM servers."
Sounds as though these aren't meant as CTF maps, so I wouldn't worry overly about their "skiability".
I think Stygian's terrain looks ridiculous, but it plays quite well: the excessive undulations allow dm'ers to gain speed and alter their paths quickly.
Sleepwalker's the polar opposite, in both terrain and playability. Legions' slow, floaty movement doesn't support flat terrain; at least not with snipers. I suggest adding some hills and removing in-base vantage points.
You'll also want to consider scattering spawn points along the sides. Because there aren't weapon pick-ups, powerups, or control points, teams are free to camp in their base - a strategy which provides them that ridiculous spawn protection timer on top of their travel-time advantage. Disperse spawns, or, when the time comes, make deploy stations mid-map only. Teams won't camp when they're unable to pull snipers.
As an aside, seriously consider removing spawn protection. In competitive games, spawn protection is absolutely unnecessary: if there's someone camping spawns in a scrim or ladder match, that is entirely your team's fault. In public games, I can understand; in competition, though, there's no excuse. Make it a toggle.
P.S. Those players that enjoy shooting people in their FPS' appreciate the latest additions. Both the duel and the TDM servers are welcome.