I don’t think there’s anything particularly heretical about asking questions about why and how you spend your time and your resources. *For the moment,* you can certainly continue to use Max 4.6 to create plug-ins, and if you don’t really care about either nice tight timing with regard to the Live transport or having some access to the LiveAPI, then stick with the old ways. Marcel’s vocoder will run perfectly well as a plug-in constructed in 4.6 or as a M4L plug-in.
But that’s *now.* No guarantees as to your future. If you’re content with that, then go make some wonderful music and hope that the current situation lasts. You’re the one that gets to make that choice – you can be the grasshopper or the ant.