I remember in older editions there was rust spells, like Touch of Rust, and the like. Seems like they got rid of that line of spells, was wondering why? To game breaking? 

Most enemies don't have anything you could even target. Look for discussions about Heat Metal for evidence of this.

Quote from Sanguisuga01 >>

I remember in older editions there was rust spells, like Touch of Rust, and the like. Seems like they got rid of that line of spells, was wondering why? To game breaking? 

It's sort of like sundering weapons in 3.x -- super annoying when done by an enemy, and useless to PCs because you're destroying stuff you could otherwise loot after combat.

I can see those reasons. Does seem to be more of a utility spell over a combat spell, damage doors and locks,  etc. 

Sometimes i miss the flavor some of the older editions had, simplifying things has its drawbacks.

In general, WotC has tried to move away from having super-specialized spells in 5E the way older editions had.  Rust spells were basically good for only destroying enemy equipment or harming Iron Golems and very little else, so out they went.