Why no love for twisted treeline?

I know I am part of the minority that still plays 3s, but why does it feel like RIOT forgets that they have a 3v3 map when they do the event missions? Twisted Treeline can be part of the alternate options, just like ARAM is used for some missions, but the complete lack of consideration for this map seems a big oversight. You could even try to get people to branch out and try the map by including it.... what a thought, encouraging people to branch out to all of your maps.