I'm guessing you've never worn a 1655... Dials with no markers are fine, but the 1655 dial is a nightmare to read, because the eye picks up on the additional 24hour markings instead of the main ones. For example, the eye sees the first marker past 30, and thinks 35, but it's not, it's actually 32.5, and then the mind re-calculates, and it gets a bit rather than simply looking at a glance and easily reading the time. You may well be one of the lucky people who can wear the watch and tolerate the dial. The effect is impossible to tell from photos, only possible to experience while wearing the watch, but is incredibly pronounced.
Lets put it another way... If the dial format for the 1655 is perfectly acceptable, why do you think Rolex discontinued to use the dial, and proceded to built the next generation of Explorer II's with GMT/Submariner-style dials and continue that style to this day?