When you seek to replace a sample inside of an instrument, you almost always will have a specific sample in mind already. However, when your .sf2 has a lot of samples in place, it can be a pain to scroll through and search for the sample you have in mind. This is especially so if the sample's name shares the same few letters to start with as several others, or worse, has a name whose only unique quality is a series of numbers and/or letters at the tail end - such is the case with video game rips, oftentimes (e.x. "Type 1 0x13c18b").
There is always the option of searching up the sample and dragging it into the instrument, or right-clicking it then adding it to the instrument, of course, however "Replace by" negates the need to fill out all the parameter cells a second time, a major time saver in the case of large KeySplit instruments.
Speaking of which, a search bar for the "Bind to" prompt would also be prime, given its close relation to the "Replace by" prompt both in menu placement and challenges.
