You only need a feat if you want to attack with multiple weapons in the same round. Nothing stops you from having a Rapier in one hand and a whip in the other, and attacking with the whip when you're 10 ft away, and the rapier when you're right next to your opponent.Not without a Feat, and with that Feat you could use a d8 weapon instead of a d4 weapon. The only reason to use the whip would be reach, which isn't really that useful. If Whips were "light" then, I agree, we wouldn't need a Feat. It would be a choice between d6 or d4 + reach. That seems like a good trade.
And if it is a Feat, then it has to be one that can compete with Dual Wielder (or whatever it's called).
The whip's advantage is that it is a Finesse, Reach weapon. It gives up a couple of points of damage for being able to attack from out of normal melee range, such as from behind your tougher characters. If you're not making use of its primary advantage, it makes sense to use a weapon that doesn't have it if you want the minimal damage increase.
There is a specific feat designed to grant the simultaneous use of non-light weapons as dual-wielding. I don't think that being able to pick the best advantages out of other feats and combining them is a good way to balance new ones.
It shouldn't be "competing with dual wielder" because it shouldn't be granting the same effect at all. As with all feats, you should get benefits for taking both if you wanted.
I'm not seeing that happening. Exchanging a couple of points of damage for Reach isn't being punished.I'm not a hard-core powergamer, but nor do I think that players should be mechanically punished for RP choices.
If you make it automatic as your previous suggested feat (did you mean Acrobatics or Athletics?) then as you have written it, it would be expected to apply to every situation you were making that check, whether you were making the check to reduce your falling damage or to wriggle out of a grapple.Not sure which question you're asking here (did you mean "wouldn't" instead of "would"?) but...
1) I think it should require a feat for the above reason
2) I was looking to add utility outside of combat to make it more interesting
3) The problematic part is which Athletics/Acrobatics checks. The three choices are "DM's discretion" "If there is an anchor point" (which to me sounds like DM's Discretion) or "Always". Not sure what the best answer is.
Doesn't that "logic" apply to every weapon in the book that isn't already a monk weapon though?Nor I, but that doesn't mean that it couldn't be, if somebody wanted to be creative. And if it's not a Monk weapon then no Monk will ever use it. (Not just for the damage but because some abilities require Monk Weapons to be used.) I don't see a reason to not allow Monks to join in the fun.