IMO, US 412 should also be upgraded as an eastern extension of I-155 in TN too between Dyersburg and I-40 in Jackson. US 412 in TN and the above proposed upgrade between I-35 and I-49 would be the easiest sections of US 412 to upgrade to interstate standard anyway.
US-412 is already a freeway between Dyersburg and Jackson, just not to interstate standards. It's only limitation is the exit ramps to it from I-40 at Jackson. Does the AADT really support this kind of upgrade?
Also what about US-412 to/from Kennett AR? Would ArDOT turn it south to connect Paragould, or would they run it straight to Pocahontas to reconnect at Imboden?
I have driven US-412 between Portia and Hardy many times and it is rough country to punch a freeway through and that usually means lots of money.
I don't disagree on the needed updates to US-412 around Springdale (Springdale Bypass) which are in progress. ArDOT has put in a lot of passing lanes on the route to Mountain View and updated the rest to Harrison.
But between Hardy and Imboden, get the checkbook out.