The feedback on these maps is highly appreciated, so thanks for making this thread. I'll try to respond to each one individually as best I can, and expand on anything that Elf hasn't already brought up. Note that some maps simply aren't there because we wanted to remain conservative to start off with, and ensure we mostly had standout maps upon launching the server. Of course these calls were made based off just mine and Elfbarf's opinion at the time, which is why getting feedback now from TTT regulars is something we really wanted, as we're here to make the server for everyone. With that being said, some maps I'd unfortunately have to veto due to them not being conducive to all that great gameplay. I'll elaborate on this further below.
ttt_minecraft_b5 - A fine map. Can be added without issue granted enough people want it, but like Elf already said we didn't want to add too many minecraft maps as we have already replaced 3 classic maps with their Minecraft counterparts; they also run and play a lot better than their originals (special thanks to Vader and Marshall for these).
ttt_borders - A very nostalgic map as it was the original SG server's default map, and so whenever the server would crash (spoiler: it was a lot) this map would be played. Unfortunately looking at it through an unbiased lense it really just isn't a very good map. Elf has already gone over the technical issues the map suffers from as well as the gameplay elements, but I'll expand a bit. The map really only has one main area which isn't all that big, and ends up being where the majority of people just stand around waiting for the traitors to do something. This boredom in the past was usually offset by people playing "loosely", meaning prop RDMing and explosive barrels. This is something we massively wanted to avoid as it is what emptied servers in the past. People would die within the first minute of the round (innocents and traitors alike) to someone bringing an explosive barrel into the middle of a crowded group, where it was only a matter of time before someone decided to shoot it for 'fun' and pretty much ruin the entire round. Borders is unfortunately a hard no.
ttt_Clue_se - Already on the server in the form of an updated 2017 map which fixed some technical issues and added a bit more visual flair to some areas.
ttt_forest - An alright map. It was actually something I wanted to add out of nostalgia but when testing we realised how limited it actually was. Like Elf already stated it's just a big loop with no real branching paths which makes for limited/deathmatchy gameplay. I wouldn't be too opposed to adding it if the demand is truly there, as I feel it would be okay on lower pops, but anything higher than that and the flaws would start to show.
ttt_minecraftcity_v4 - My thoughts are pretty much what Elfbarf already stated.
ttt_equilibre - Technical issues aside, it makes life very easy for traitors with there being inaccessible water all around. Being able to dispose of unidentified bodies so easily just breaks the game mode and things become a mess very quickly. Body disposal is typically done through limited or risky means, such as the flare gun (a traitor weapon that costs a credit and still leaves scorch marks to at least show that something happened), or through the magneto stick by hiding bodies in traitor only areas. Having it be accomplished so easily just puts innocents on higher alert than necessary and it ends up becoming an RDM fest due to the increased paranoia. The detective can admittedly purchase binoculars to offset this slightly, but as they are often prime targets and their credits are already very limited, it just feels like too many bandaids are needed to make an otherwise poorly made map somewhat playable.
ttt_foundation_a1 - See Elfbarf's reasoning.
de_dolls - Like Elf said, large rats style maps like these just end up in scouts being the only real effective way for traitors to accomplish anything which makes the gameplay a bit too one-dimensional, as so many other methods of murder will simply get you spotted. Gameplay tends to devolve more into a deathmatch style as a result.
That covers it for now. Feel free to respond and give further feedback, but I hope our posts helped shed some light on why some things didn't make the cut or were outright rejected completely.