If you do it right, you don't have to the lookups in main memory.

We have a c2758 doing 12mpps l3 routing (full BGP table) with 50 ACLs on one of these: https://netgate.com/products/xg-2758-1u.html

The c3000 prototypes are due in a couple weeks.

Now I'm wondering how one of the 16-core chips would handle VyOS...

Won't be any faster than what you have today.

Right now I've got a little EdgeRouter X - it would probably be faster.

Hard to compare against the Cavium Octeon. x86 general purpose vs MIPS64 with dedicated offload hardware...really depends on the use-case. I have an ERLite and AFAICT it competes with stuff way above it price-wise, e.g. https://store.netgate.com/ADI/RCC-VE-2440-board.aspx

I'd rather run PFSense, but it's not worth an extra $200+ for just my home use.