Ok, just dumping some thoughts about what little thinking I do (ha!) when thinking about a new class.
XP progression.
Noted this when I was doing my pc_gen app data entry. I think Francisca also clued me in when he was doing some 1e class creation stuff.
Here are the different XP progressions by class, from lowest xp needed to get to 2nd level to highest. Also as a lark, the base hd for each progression. First one listed is for the class. Others listed after are for classes that follow that progression. The "xN" notation to denote more than 1 class with that HD for that progression
thief: d6
assassin: d6x2
fighter: d10, d8x2, d4
cataphract: d10x3
magician: d4x4, d8x2, d12, d6x2
paladin: d10, d6
barbarian: d12, d8x2, d4
Interesting that most of the classes use the magician progression.
Just putting this here as I work through the tinkerer/scavenger/gadgeteer/whatever class in another thread