Personally I preferred the Protectorate question over the Ireland one. My basic structure was:
For:
*Council of State being largely army officers - caused discontent in the 1st PP who wanted less army influence + reduction in the army. They refused to pass any of the ordinances that O.C and the C.O.S had drafted before the meeting due to this.
*A bit about the M.Gs, how they were disliked
*2nd PP wouldn't vote for the Desimation tax which funded the M.Gs, leading to the end of the M.Gs and annoyed Cromwell - settlement less likely
*Members of the 2nd PP being excluded by the C.O.S to try and make meetings more successful - heavy army influence and after a month attempts at settlement/reform broke down again
*Bit about the army wanting radical reform but governing class mainly being more moderate, linked to the regicide/Pride's Purge/etc
Against:
*Some historian quotes (Coward and Hutton) saying O.C would never be able to work with a parliament
*1st PP attacked O.C's authority directly, e.g the legitimacy of the constitution
*Cromwell himself wanted religious reform but parliament were against any radical changes
*Aftermath of the civil war - parliament were reluctant to make any large social/religious changes
*A little bit about the regicide and how it hadn't been widely supported, and was only a 'last resort' after negotiations came to nothing. Cromwell was linked with the regicide so settlement made difficult
*Opposition to Cromwell - in the 2nd PP Haselrig claimed all government since the Long Parliament/Pride's Purge had been illegitimate
Conclusion:
*Summary of all points and concluded that military basis was the main reason for the failure to reach settlement
Honestly I would have done anything else above Wentworth in Ireland, I know next to nothing on it.
It seems quite a few people did Ireland over Cromwell though.