I don't get what Bose is saying at all. Virtually all our M/E fleets have a requirement for close formation and it would be utterly ridiculous to take an RJ, E-3D or P8 out of operational service to teach multi-engine formation trip 1. Formation flying gets harder as aircraft size increases - in IMC and on the wing your eyes can be a long way from the fuselage you are formatting on. Add in heavy aircraft inertia, large turbine engine spool-up time or turboprop effects on trim and lift you can have a lot going on.
If the Phenom is not up to the task (and that is a very big if) the solution is not to kick the can down the road and try and teach formation basics on an even more expensive and challenging aircraft.