It's hard to determine how much is bloat and how much is essential software. Much of the "bloat" issue depends on how many aspects of the program you want to use. If you only want to use it to rename your photos and folders, there would be no need to switch from BreezeBrowser.
If you want to use ZoomBrowser for its other capabilities, then only you can determine if it's good for what you want to do.
With the ease of installing and removing software these days, my advice to you is to install it and see if it does what you want. If so, keep it. If not, remove it.
I measure bloat for subesquent versions of programs I use by how much A)larger and B)slower the subsequent version is when compared to how much improvement and additional features it adds.
Just because a program is large on the hard-disk doesn't mean it's bloated, if all that code is useful to obtain the results you want. And just because a program has a fairly small footprint on your hard-disk doesn't mean it's any more efficient or capable.