don't like the combat system? how about trying the auto fight function?
a couple years ago i was playing the japanese version (mother 2) with a japanese speaking friend of mine who is a very casual gamer (except for street fighter 2, heh). since we were enjoying the script more than the fighting, he would always choose the auto fight function in battle just so we could get back to the story. really, the story, the characters, the music...superb.
from a hardcore gamer standpoint, it's blasphemous i suppose, but if you don't like the battle system it's a nice way to sit back and do some small task while the computer fights for you (assuming you have sufficient items & healing PSI, etc)
mother 3 has an improved battle system based on the background music, which is really fun. regular attacks done to the beat of the battle song result in long chain combos. the fan translation is amazing and i recommend it to anyone who is a fan of 16-bit RPGs in general. the same translator also retranslated mother 1 (aka earthbound zero) for GBA, and this is the version to play. the first game is very old school and not on the same level as the sequels, but if you enjoy earthbound and mother 3, i would play the
mother 1 GBA translation.
the stories for the 3 games are only loosely connected, so you can pretty much play them in any order. i suggest you play mother 3 after earthbound, then play mother 1.