Li Shenron
Legend
Double post :/
From a streamlining point of view, eliminating the bonus action makes sense. However, this is one of 5e's interesting tactical considerations in combat (what should I do to get a bonus action, if I have multiple choices which one do I take etc etc) and I fear that removing it may be *too* simplified.
I get why they had it cost a bonus action though. Without any other abilities such as fighting styles and Feats, dual-wielding shortswords allows you to do 1d6 + Damage Mod with one attack and 1d6 with the other, for a total of 2d6 + Damage Mod possible damage per turn. A Greatsword also does a possible total of 2d6 + Damage Mod per turn. But the dual shortswords gives splits that damage up between two attacks, which slightly increases its average damage per round. Not by much, but having it cost a bonus action helps to balance out the slightly higher average damage and potential to go Dex-based.They can also change two weapon fighting to: "When you take the Attack action and are wielding two weapons with the Light property, you may make one attack with your off-hand weapon as a part of the Attack action. You do not add your ability modifier to damage for off-hand weapon attack." Although, realistically, they could've (and should've) worded it that way already.
I can only assume the vagueness catered to a specific subset of DMs that for whatever reason had a hard time with rules lawyers. For every DM that prefers consistency, there is another that likes ambiguity. I guess in the that sense 5E appeals to a large base of DMs.