My biggest problem with account bound items is:
1. If I buy an item, then I don't like it (i.e. a change kit), I'm stuck with it.
2. There isn't even a gift e-coins option on the website anymore, so if I wanted to buy someone else something from the cash shop, or give them the e-coins to do so, I have no way of doing it.
3. There is no point in making BB+ account bound. To me, the whole point of a BB+ was to give premium to people who couldn't afford it. Of course now, it's just a way to get more bonus exp, but who wants to spend that much money on buying both?
4. Estsoft could be making even MORE money off people who would buy extra stuff to either sell it or give it away to friends, so why go backwards?

Hopefully, they will change it back again.
They wanted to make account bound items so that some players didn't gain "advantage" by selling them. Essentially, they're still giving those people an advantage anyway!