Warmfront was a fun map - particularly the mid. There were attempts to transform it into a sort of KOTH map after it fell out of favor, but I don't think that materialized very effectively. I also really liked the second point.
The main reasons it was removed:
Last was very unpopular. It's huge, so the "tag-bomb" rinse repeat was really hard to execute if impossible to use effectively given the distance you had to close (prolane and freight had a similar issue). On the defending side, if you lost most of your team defending, it was really difficult to push out to second because of how much distance you needed to cover to get to second, and how relatively exposed you were on the point once you got there.
During LAN Enigma held middle by getting a heavy on house which made it extraordinarily difficult to push middle and foiled many pushes, even those with advantage - simply because heavy is pretty good when he has the high ground and is in a defensive setting. Gullywash/Badlands have similarly good heavy spots at mid, but are big enough you can get around him, your options are more limited in on warmfront, but some of its effectiveness is related purely to the LAN environment and how rare heavy play is/was.
Some people complained about the FPS performance loss on the map due to lack of optimization present in the map at the time.
There was a hilarious strategy that was actually used wherein you could have your scouts drink crit-a-cola and stand with the short stop at the top ramp on mids and any soldier that jumped just got instantly vaporized lol.