I think you're missing the point. You're a network engineer and know what you are doing. Most people aren't.
IP4+ would be easier because it's more incremental and less change than IPv6.
Yes, there exists solutions to all the problems that IP4+ would solve, but the point is backwards compatibility and incremental change is always easier than doing something new.
But, correct me if I'm wrong, IP+ doesn't do anything differently from IPv6, except that it changed the 6to4 prefix?
Host 1.2.3.4.5.6.7.8 still can't communicate with a "legacy" host 4.5.6.7 without some kind of bidirectional translation mechanism. Just prepending 0.0.0.0 to an address (or 2002:c000:0204, for that matter) doesn't fix the problem.
IP4+ would be easier because it's more incremental and less change than IPv6.
Yes, there exists solutions to all the problems that IP4+ would solve, but the point is backwards compatibility and incremental change is always easier than doing something new.