Don't nerf Tequatl, but raise the time limit
No need. The most hard part of the dragon fight is the first %25 dps race. After you pass that stage, killing the dragon takes mostly 2-3 more minutes.
In Desolation, we killed it in 10 minutes. So if you can organize the people in map, 15 minute is enough.
In before low/med servers and stuff things, timer can be scaled according to the number of people in it. However, it can be abused easily.