The easiest comparison is New City - Arnika.
They are extremely similar, and you can easily see where the roots are coming from (which is why I play - not because I don't like Wiz8 more, but because I am interested where good things I liked in it come from - like the magic system with afflictions, ability to turn monsters on each other, make them flee; and overall design changing).
In New City, I met 25 hp guards and some 45 hp guards. I return after 6 levels, and I meet 45 hp guards.
In Arnika you meet 16-18 hp borgs, you return and can meet 100 hp borgs.
So if I would choose between:
a) fast roads, death dungeons
or
b) death roads, death dungeons
I'd prefer designer sticking to a).
the hell-unicorns are relatively low level
Doesn't matter if mobs are technically not as high level, what matters is their strength relative to party.
If party at that time mob spawns will probably always be underequipped to deal with them it's not great.
If encounter is some sort of story unique and you gotta be smart and avoid it, is ok, but in a system which just well infinitely spawns monsters, spawning increasingly higher level shit all the time between locations is not the best thing you can do.
In that respect I like M&M6-8 system more. I also would have enjoyed some sort of lair/destroy lairs/spawn lairs/make roads great again system.