I think you pretty much answered your own question. However, I'd argue the less buttons there are the less need one has to macro. Also, just because one has a macro doesn't mean they always have to use it. MMOs have morphed from thinking more to hours of button mashing, and especially with games like EQ2 and even some WOW classes if you are playing for extended periods of time it's brutal if you aren't 25 and also work on a PC during the day.I never understood macro rotations doesn't that take all the fun out of actually playing the game? To each their own but just sitting there press one button would get old real quick for me. I know essentially all I'm doing is pressing the same 6 buttons but still...
The bigger advantage of macro keyboards is the ability to do things faster than most human hands can, and it's a huge advantage in PVP, especially if you can circle strafe and use multiple abilities right at their global cooldown and mash multiple buttons simultaneous via one key.
The game, story, talents, and thinking to me are fun. Mashing the same keys in sequence over and over, not so much. I'm not sure how anyone plays EQ2 without a G13 or G15.