The opposite to the "Kill it with fire" thread, pick something that 4th edition (or third, or even earlier) dropped from the game but shouldn't have.
My list:
* Playable Monsters: 3rd edition went overboard with this (Anthropomorphic Baleen Whale?) but the idea of a "monster party" is cool. Definitely something for a splatbook.
* Spells are spells, combat maneuvers are combat maneuvers. While I don't mind using power format for both (lower learning curve), 4th edition had no descriptor or anything to set them apart. There was only the cruddy weapon / implement split, and power sources, which had no game effect.
This made it difficult to make antimagic or wild magic zones, bound and gagged wizards to prevent spellcasting etc.
If 5th ed uses the power format, add a "spell" or "supernatural" keyword.
Setting both clearly apart might have warmed up more people to the 4th ed barbarian...
My list:
* Playable Monsters: 3rd edition went overboard with this (Anthropomorphic Baleen Whale?) but the idea of a "monster party" is cool. Definitely something for a splatbook.
* Spells are spells, combat maneuvers are combat maneuvers. While I don't mind using power format for both (lower learning curve), 4th edition had no descriptor or anything to set them apart. There was only the cruddy weapon / implement split, and power sources, which had no game effect.
This made it difficult to make antimagic or wild magic zones, bound and gagged wizards to prevent spellcasting etc.
If 5th ed uses the power format, add a "spell" or "supernatural" keyword.
Setting both clearly apart might have warmed up more people to the 4th ed barbarian...