So I re-read the OP and I thought on it some.
I finally voted (yeah yeah 2 years late blah blah) because someone posted in this thread today and I had JUST watched Chippy's video about Terraria Re-Loaded or whatever that mod is called, that adds in all the new effects n' such, which is somewhat like this thread is trying to suggest.
I voted 40% and "Only New Items". I do not want past items modified; I LIKE my Yo-yos and Terrablade just as they are, thanks.
One of the questions the OP posits in the thread, is "Why would you use anything else?" Well, there are several reasons why:
1). Melee Armor tends to have lots of tanky stats and melee in general does slightly less damage -- you get more defense, but you dish out less damage in return. Compare that to Ranged Armor, which is pure damage output with some Stealth (that also has damage benefits).
2). Ranged Weapons usually use interchangeable ammo for different effects -- some are seeking, some have Ichor applied, some bounce off of walls, etc. You can't do any of those things with the Terra Blade, Meowmere, or a Yo-Yo. Well, ok, Meowmere bounces off walls and Flairon seeks, but they are not interchangeable and are locked to those weapons and only those weapons. I can't make a Meowmere seek or a Flairon bounce off of walls.
3). "Why use any other melee"? Well, Solar Eruption says "HI!" Pre-Solar Eruption, I use a Yo-Yo when I want consistent damage on a target while being able to move around and even duck behind walls. Yes, I use the Eye of Cthulhu yo-yo over the Terra Blade in some situations, especially against the Cultist Leader the first time. I'll swap to the Terra Blade when I want to stay back, such as a highly mobile boss fight, or if I want to lock down a whole hallway in the HM Dungeon.
So really the main premise behind the suggested changes to older weapons doesn't really hold up.
Now, I voted 40%... on the grounds that I am somewhat interested in seeing NEW weapons with NEW mechanics, like the Solar Eruption. Most awesome piece of kit, like, ever. And it is fully melee, it just has a ginormous range and it goes through walls... almost feels like cheating, haha. But I love it!
That doesn't mean, though, that there might not be a new weapon that comes later that I might use in other situations if the mechanics were enjoyable and/or weapons that are added to earlier progression. Tremor mod added a ridiculously awesome sword that adds spider eggs, that acts just like the spider turret only it's a swung sword and that is a heck of a fun weapon to use (though to be honest, it strikes me as something that should have been on a gun instead).