You know , one thing I see rarely get brought up is how people like to play SMRPG.
It may seem silly , but I find the game pretty flexible in term of how you want to play it. You can totally stick to a party of 3 characters and leave the 2 others to collect the dust , you can only upgrade one stat... Or heck , with "
The Hammer from Seaside Town TM" , you could technically do a level 3 run.
For more infos on that hammer :
I personnaly played through the game two times , once normally (Using all party members , taking my time , all of that) , and once with a Mario/Mallow/Geno run.