No additional details at all have been given about the 401/VMP interchange.
From what I know there are three possible designs at this point.
1. Status quo. (Trumpet interchange that exists now)
2. Reconstructed trumpet interchange. The loop ramp's circumstance would be much larger, making it safer as the turn is not as sharp and allows for higher speeds. The ramp from 401 EB to VMP (NB) would also be not as sharp and be widened from 1 to 2 lanes.
3. Parclo A-4 extending the VMP south to Wilton Grove Road. This means stoplights must be built for 401 EB to VMP NB and 401 WB to VMP SB. A parclo also means the interchange is no longer free-flowing and significantly decreases the efficiency and capacity of the interchange.
I think a Clover-turbine interchange (also known as a two-level cloverstack) would be the best option because it is free-flowing and is relatively cheap to build (only 2 levels). Weaving is eliminated on this junction too.
Pic of the junction:
Build this type of junction if you want to extend the VMP south! Since the land around the 401/VMP is undeveloped, secure the needed right of way now!
Also why no talk of a northern extension of the VMP? An extension north is more justified than an extension south in my opinion.
EDIT: I asked Joe on his Facebook page about this interchange. I didn't want it to be too formal so I wrote on his wall lol!