The only people I am aware of that don't like this change are people trying to undercut other listers by a small amount on high value items, knowing that the penalty to cancel and relist protects them for the listing period of their competition. You can no longer do that effectively, and frankly it was cheeze to do so to begin with.
The old deposit meant I would leave my item listed even if I got an offer in person of 95% value. Even if someone was willing to pay asking price, you would go through the GTN, because losing your deposit was worse than using the GTN cut. Now, there's no reason not to harass GTN sellers with offers below listing price, since they lose only a few hundred credits of deposit on some of the game's most valuable items.
Beyond that, the constant relisting at lower prices may be good for the buyer, but that's really worthless. People who are producing high value items in any significant quantity are going to have the same effect on their inputs, so margins should be pretty stable (at the 18% crit rate for mod sellers like myself).
It is, however, annoying to those of us who list things at fair prices for long duration to have every "cheeze" seller able to relist and undercut at a moment's notice.
There are people without bank tabs using the GTN as their bank, since listing something for 350 million credits is little more than storage.
The misclick-predator high price listings are also encouraged by unlinking the deposit from the true value (asking price) of the item.
The new deposit system is both inflationary and annoying. Please revert or explain very clearly how this is better.