...You do have a point that a new person doesn't need all the extra bells and whistles, but my main concern is putting the training instrument and the professional instrument side-by-side in one room. Without much know as to why one should play on the training instrument first, they see the professional instrument cooler and will opt to do that instead.
Incoming players mostly play songs they like. Why would such player want to play their favorite song tv size when there is a full version in another diff? I see new players boasting about how they pass 5* diffs with a bunch of misses, and then make threads in G&R complaining that they are not getting any better. I speculate this will give them even a bigger incentive not to play easier diffs which have the map cut short.