The real issue isn’t that they necessarily have timers, but in how they are implemented into the events.
In the case of Tequatl, what they should have done was have a somewhat generous timer for the opening of the fight until you get Tequatl down to, for example, 75% health. After reaching that initial damage race the players should have a chance to use the siege weapons to “severely injure” Tequatl, thus removing his ability to escape.
They could also use a modified version of this and have the players be able to “reset” the timer at certain health intervals by severely injuring Teq (I personally prefer this one, as it can require players to be actively involved in the event).
The problem I always had with the Dragons had nothing to really to do the difficulty level (although I do love a skill based challenge, dps races are just boring as hell when it essentially forces players into a “speed run” format or mentality); the issue I always had with the dragons was the lack of involvement in their events.
- Waves of enemies, requiring groups of players to run “crowd control”: Good
- Support elements playing important roles (i.e. the turrets for control, clearing aoe fields, etc.): Good
- Time gates that have some sort of mechanic that allows players to intervene and interrupt an enemy “escaping”: Good
These kinds of things require players to be alert and active and make things more fun as well as challenging (unless really watered out, you can’t just be lazy with these types of things).
- Straight up time gates: Very, very bad idea
A straight forward time gate for events like these, especially ones like Teq, are just about the laziest, most uncreative, and boring thing you can do; not to mention it just kills any sort of fun or “real” challenge as it just waters the event down to a straight up dps race with just straight up zerging the event to win. Boring.
I like it when events are difficult enough and/or just dynamic enough that they can be failed, but failing based on a timer that forces it into a massive zerg rush on the scale greater than anything yet seen in the game so far is just the opposite of what needs to be done.
Force the players to divide up to work at different parts of an event; control factors, support functions, etc. and make these other elements enough of a hazard that if ignored will overwhelm the players to failure.