I'd say they can make a formula where all ilvl gear is in mind. Make a Gauss' bell and escalate the Bosses HP so they last at least to see the main mechanics. SE knows how long each fight has to last to make it interesting and engaging to new people.

Lots of ppl will go "Waaaaaah, CT doesn't last 8 min or so! (´；ω；`)ｳｩｩ" I'd say that when there is a lot of high levels, rewards will escalate as when the system rewards you for new ppl trying to get a clear.

Many old content that was fun (and yes CT was fun on its release) is now a snorefest. If it means that the raid will last longer, it is fine in my book.

Ppl are entitled to say they want it to last 7 mins, but geez its boring as h*ll. xD

My two cents.