Riot has made their intentions clear, they want to focus on Shadow Isles, the new Twisted Treeline, because it's in Beta. They want it to be the best it can be, and have shown it by changing things around that players are concerned about. Obviously, they can't appeal to every single suggestion, but they've pretty much made changes and tweaks to the map every single patch.
Some people suggest to just make the new Twisted Treeline its entirely separate map. I'm certainly not against this-- I've played the old Twisted Treeline just as much as anyone else, and fell in love with it. It certainly did have its own issues, but it seemed like those issues could have been resolved without completely changing the map. I'm sure some Riot members themselves have had fond memories of playing it.
All I'm trying to say here is that Riot tries its best to appeal to the community while making a game that they'd enjoy. That being said, it would obviously be a bad idea to try and work on two maps at once. It means they'd have to split their workforce, and overall things will happen a lot slower. I'm a fan of both Twisted Treelines, and for the most part, prefer them over any other map variant. But Riot has made it clear that they still do care about our opinions on the old Twisted Treeline, but right now they'd like to focus on the new one. I feel like it's dumb to complain about it and continue posting threads about how much you hate it and how Riot doesn't care, because all that is going to do is make them ignore the community!
Riot's agenda seems pretty set--They want to finish the new Twisted Treeline and get it out of Beta before doing anything else. So instead of making these threads about how much you hate so-and-so, or how you want the old map back, just focus on the new map and changing it into a map people will enjoy. If you show interest in improving the map they're currently working on, but retain a love for the old Twisted Treeline, I'm sure something can be arranged. But currently, if I was a staff member of Riot and saw this forum, I wouldn't be too encouraged to listen.