When using mesh helpers and spines to rig imported mesh then the process gets exponentially slower the more spines are added. For example, when rigging mesh as seen on the screenshot, it takes around 7 seconds to compute when clicking “Send Spine” and assigning it. Even when just selecting the rigged mesh there is a freeze of several seconds. After assigning automatic weights and starting manual clean up, even just selecting one vertex freezes everything for another ~7 seconds. For this example the leaf consists of two parts, so I have to select 2 vertices, then I use “Matching colors” to select the whole thing (I have pre-assigned vertex colors) and then picking the spine also freezes everything for many seconds, so basically three clicks takes around half a minute of waiting, that gets annoying quite fast, so maybe there are some optimisations you can make to the process.
Also, when setting the point sequence on the mesh helpers, it is quite difficult to get the point to appear where I need it to be, I assume it tries to find some middle point in geometry, like holding T when positioning the start and end points, but it often places them in the wrong place, again I assume that also some geometry in the back of selection (sometimes even many layers) is taken into account and the point is placed through the area I want it to be in/on. So maybe there could be some setting that could be changed determining some radius where the mesh distances are taken into account and ignores everything further away. Or for flat leaves just a surface snapping option would be also very good. I know the spine points can be changed in Freehand mode but that is also almost unusably slow when there are many spines.