Grand Exchange: Why not make trade easier?

Are there good reasons not to implement something similar to the Old School Runescape Grand Exchange system to trade items seamlessly with other players?

Having one very clear location you can teleport to that is just used for trading other players and with a grand exchange-like system at its centre could be a nice social hub and streamline trade.

The current currency exchange feels very clunky/basic right now, with no ability to look at trade history among other things. I also think its UI and locations aren't very clear for some players, and so you have players in the trade chat constantly spamming "WTB 1 div each 45 ex" etc. trying to take advantage of players who don't understand how it works.

Trading with players often has you trying to contact AFK players for long periods, or lagging out as you teleport to someone on a different server. I also often miss my own selling opportunities as I don't notice a whisper me mid boss/map.

Maybe I'm missing an obvious reason this is a bad idea!?