I support Renshi 100% in regard to their opinion on the OP.
This feature is most certainly NOT DESPERATELY needed. There are many, many, many (as many manys as you feel make the point) features which need to be reformed before something like this is even considered, let alone implemented. SE should be ashamed that something like this was even brought to the attention of Yoshida-san at this this phase of the rebirth of XIV.
Before anyone jumps down my throat to chastize me for disagreeing with something which the unwashed masses clearly feel is necessary to their enjoyment of XIV, I would like to unmistakably point out that I am not against the concept per se, only that I am 100% against the application of ANY resources on a subject which is so obviously unnecessary at this point in time.
If you don't want to sell something, then make certain you are not selling it. If you sell it by accident, then deal with the consequences. You have made a mistake. TOUGH SH!T. Learn from your mistakes and do not repeat them.
I have never, NEVER, accidentally sold an item; and that's after 6+ years of XI and ~9 months of XIV. It's not difficult, I promise, you simply have to actually read what you are clicking on and making sure that you aren't just rushing through the menus.
If the UI is "too laggy" and it "makes" you sell an item other than that which you actually intended, or you "didn't notice" that you were selecting an item other than the one which you intended to sell, you need to SLOW DOWN and actually READ. I know, I know...reading...in a video game?!?
"It's a tad to easy to sell gear..." ARE YOU SERIOUS?!? How many buttons do you have to press before you actually sell the item? And yet it's too easy for you to accidentally sell items? WOW!
Oh yes, and one other item: feel free to call me a troll, or to refer to my reasoned and explained arguments as a wall of text, I realize that reading comprehension and the ability to connect multiple thoughts into a coherent agrument are two mental abilities that most people cannot hope to possess.
TL;DR quit being so lazy, I bet you'll sell fewer items accidentally
p.s. Mad props to Renshi for taking a stand; to Danny52844 and Scape for voicing their opinions, and to Dreamer for taking a sensible approach to the situation.