The E175 (current generation, not the E2), is already restricted in weight due to scope. It’s MTOW is 89,000lbs but scope keeps it below 86,009 (except for the Compass E175s). As mentioned above, scope is bringing the CRJ550 weight down to 65,000lbs (down from 75,000lbs).
Restricting the E175E2 or the MRJ90 weights below 86,000 would really restrict payload and range.