We've had Reaper for a little over 2 weeks now, compared to a minimum of 2.5 years for the rest. Of the other jobs, how many can you say for certain that you were able to play it with minimal looking at your hotbars after only 2 weeks. Also bear in mind, Reaper starts at 70, other jobs start with less, so it is arguably easier to slowly build up the knowledge required to look at hotbars less.

All you need is more practice and familiarity with the job.