These sets seem extremely ambiguous and not like any known mechanics already in the game. It's one thing to be creative, but another to suggest things that don't really fit anywhere into the game. The mechanics and systems needed to implement these sets are not only hard to understand and get used to, but i would assume break current game mechanics requiring a complete rework of the entire game.

Shield set: having the armor mimic the shield seems unnecessary, as all shields (besides swift strike, scarlet and thorn shield) only have defensive stats, most of which have direct armor translations. Having an infinitely recharging shield on at all times means that avoiding damage for a few seconds makes you invincible, something that can be easily exploited. Also it is impossible to wear "nothing" for armor, and if it were possible i would assume it would always result in a 1 hit kill, as that's pretty much how it works already with the weakest of armors currently, so any attack that can break a shield in 1 hit (trojan smash, vana mace, lumber smash, etc.) would instantly kill the knight. And having a party wide defense bonus whenever hearts are collected means that in places like FSC areas you can have infinite defense ups when a heart generator is near battle. Plus coping UVs doesn't even make sense. There is also the problem of how damage dealing status problems will affect the health of the armor as a shield is not capable of sustaining a status condition, as well as what would happen if you mixed a pice of this armor with another normal piece, especially one like ancient that boosts health (since this armor exchanges health for shield).

Switch set: forcing the player to bind another key to the keyboard just for the use of a single armor is excessive and would annoy players, especially ones like me that use a controller and therefore have a limited number of buttons to press(with the sprite skills i already had to unbind some actions that i had on before). Also doubling attack power is WAY too OP even with the defense nerf: imagine a blitz, which can already pretty much kill anything in one hit having double the attack power.

Range set: having infinite range would break the mechanics of pretty much every weapon in the game, as i would assume this also applies to the charges of certain swords. for one, as waffle said, forcing the serves to keep track of all those bullets on screen at once would destroy the servers and cause massive lag, even server crashes. And having the damage multiplier wouldn't work for the same reason the switch set wouldn't: the damage increase would be too high and kill most monsters instantly. Also guns like the alchemer line and others require the bullet to disappear at some point for it to take effect so making it go on forever would make the gun meaningless

there are many, MANY other reasons why this wouldn't work, but at this point i think you get the idea.