Jester David
Hero
Yes, they're important to characters. But that does not make keywords really different. They're a label. And not a label like "fat free" where the content is fundamentally different. As long as you stuck to your role, you could pick powers from your power source and the game would not break. (Probably exceptions but rare and not the average.)If you make sure to avoid anything that has to do with the type of abilities you use, sure. My invoker MC druid does in fact have to worry about what is divine or not, since he has abilities that trigger only on divine powers. This is the consequence of a choice I made.
It's a meaningless label, like renaming a brand overseas. You can add too it and differentiate, but the base isn't any more different.
But that has nothing to do with the damage effects themselves and has everything to do with the options added to the damage types and keywords. Remove those options and all that goes away.You can absolutely build a character that doesn't get much out of the nuances of their abilities, but that's your decision. Someone could just as easily build a character who abuses their favored damage type. Even if you never ever fight any enemies with immunity or resistances, and you avoid all damage type interactions like Frost Cheese or the Radiant Mafia or Elementals with Poison immunity, and you never play a dwarf or a shardmind or a tiefling or a genasi, at the very very least you aren't going to be using psychic, poison, necrotic damage against most objects, nor are you going to use Will attacks on them.
What you're suggesting is homogenizing the effects of damage types, but you forget how many threads involved people trying to get around the limited concepts attached to particular damage types. Many people don't want damage types to be one-trick ponies, especially since those tricks rarely stack.
Looking at the damage design independent of four years of added crunch, the different types are mostly irrelevant in terms of what powers are spells and what powers are prayers and what powers are evocations. It matters when choosing a power for your build but, at at its very basic level, different damage does not make an exploit different from a spell any more than radiant damage makes a prayer different than a spell.