Good points Diki, however no one has ever said about replacing all the sounds in an arranger, just using VSTi to enhance what is already there. (Just the same as adding 3rd party samples)

Adding 3rd party samples will always require editing to match what is on-board (Even simple Akai samples) however once setup and saved (Which with the basic adjustments required does not take long) it becomes as if part of the instrument.

Drum Kits take a bit more work due to manufactures choosing different mappings, however all Drum VST make it easy to swap the mapping around to suit, (Much easier than on your typical arranger) so again not major.

The only users that would have problems adding VSTi would be those that only use the OOTB settings, those that tweak their arrangers to suit will take to it like a duck to water.

It’s only the fear of the unknown that puts people off, but once you get past this you are fine. (You should try it Diki, as when you get over your fear of using them with an arranger that has the VST Host fully integrated, you will wonder why you ever bothered trying to put people off)

As to modern arrangers, (From any manufacture) you’re always criticizing them in features and sounds, so they can’t be that good.

Bill