I understand, and to a certain extent share your sentiments, but I think a more pragmatic approach is required. Jonathan Powell (who was right at the centre of the peace negotiations) made the following point.
"...a return to a majoritarian system of government in Northern Ireland is unlikely, at least until the province has moved beyond sectarian politics. That means there is no obvious way out of the stalemate now facing the parties, and indeed it may actually suit Sinn Féin and the DUP to return to grievance politics for the foreseeable future rather than to agree to form a stable government. If so, McGuinness has left us at a very untimely moment.
He managed to keep the system together while he was alive".
(for the whole article, which I think is rather good...
https://www.theguardian.com/commentisfre...riday-agreement )