We know that Diamond have already missed it, and not by much which I think is a very bad mistake.
Their spec for the D-Jet originally listed a MTOW just above 2000kg, and a European version MTOW at 1999kg which lost some of the useful load, a bit like the Seneca. I guess they tried but the weight crept up.
In a way it may not be a bad thing. A lot of jets flying about in IFR paying zeros fees would have commercial users whining and put pressure on the whole sub 2t exemption. If you're running a $1m airplane the Eurocontrol fees are not a killer cost - I think most operators would pay them to avoid crippling the useful load.