I don't see any problem with any emergency exit door.
Are you guys aware of different types of doors? You could, for example, install a "dual row" door, where there could evacuate two people at the same time simultaneously. I remember those door types on MD-11s (?).
Another possibility is to place two doors next to each other, like on a A320 overwing exit.
Or is somebody of you in possession of hard facts that there are no additional doors possible due to structural or other reasons? They have to redesign certain fuselage barrels anyway, and they have to prove the new aircraft in real evacuations again.
Please share with me your doubts.
Dani