Truth to be told, the same gear could produce very different results in the hands of different people.

With all Relic+1 and DL gear parties, same tank and same pulls, the completion time could differ by as much as 30%. So I'm not surprised if some people with full DL could only perform as well as some others in iLv55.

Crystal Tower will be easier than Binding Coils, that's just how the content was designed in the first place. How it performs relative to Titan HM, though, we won't know until the 17th.