I think most NIU fans are cautiously optimistic but are taking a wait and see attitude. If we start beating MAC teams (and there's really no one we can pencil in as a "W") then more will start believing.
The other side of that is there is no one in the MAC that you can pencil in as an "L" either. And both your statement and mine apply to us as well.
But at least as far as RPI is concerned, there's a distinct "top half" and "bottom half" to the MAC. As of yesterday, the "top half": Kent 58 RPI; EMU 95 (although they're 4-5 vs D1 teams); Akron 101; Buffalo 113; NIU 115; and Ohio 119. Then there's a big jump to the "bottom half": Toledo 181; BG 220; Fiami 243, WMU 247; BSU 251; CMU 280.
The RPI really only takes into account record and strength of schedule. So it counts the same if you win or lose by 1 or 100. Hence, if you get a few close wins and play a tough schedule, your RPI will be good, even if you are blown out by the good teams. If you look at other rating systems you won't see such a divide, except for perhaps Akron pretty well ahead of everyone else. Sagarin, for example, has it this way right now: Akron 66, Ohio 120, Kent State 123, Toledo 127, Eastern Michigan 147, Northern Illinois 164, Buffalo 168, Ball State 195, Central Michigan 197, Western Michigan 200, Bowling Green 202, Miami 222.