The difference there, of course, is one of necessity.
The "Word & Communion" service is supposed to be used only when it is impossible for a priest to be present on Sunday (yes, it is commonly used as a substitute for daily Mass, but this is actually illicit).
If a priest is present, you can have a Mass. And if you have a Mass, there can be no good reason to have a layman give the homily. As you obviously are quite aware, if the priest is not up to it, a deacon can do so.
Let's see how hard the Vatican pushes back. That will tell the story of whether this is a pipe-dream, or not.
I do understand exactly what you are describing, and the reason for it.
However, with the well engineered "priest shortage" here in the US, Catholics are being primed to accept such "services as an acceptable norm. This is both problematic, and evil at the same time.
While I understand that the service is used in lieu of a mass, it is mistakenly preceived in the eye of the parishioner as being a "mass" with repeated usage over time. Therin lies the problem.
Also, I have personally observed - or been made aware of - many instances when "father felt it 'hard to be present'", and let some little old man conduct one of these services, as he was off in his vacation house when he should have been at the church! Such is not an isolated case in the northeast.