If the issue is the triple whammy of activation loss and initiative loss and loss of speed (making the Faithful rule risky to use on what is likely a core Engagement formation) then why not allow the Chapels to be taken as an upgrade to a formation. One Chapel for 200pts, a second Chapel for 150.
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I took the Sisters out for a spin last night, 1000pts using the Minigeddon rules
https://sites.google.com/site/epicarmageddonlondon/minigeddonI only have 1000pts painted and don't have the models for more yet anyway so this is the best I can do for now.
I took
Mission + 4 Rhinos
Seraphim+Palatine
Retributors + 3 Rhinos
Repentance + 3 Rhinos
The plan was to have the Seraphim and Repentance stick together, diving from cover to cover, so they could combined engage using the Palatine while the Mission and Retributors went about the business of taking and holding objectives. The army rather lacked a good way of prepping targets.
I faced two Dark Angels Ravenwing focused forces.
Against the first they spread wide across the board with scouts on Overwatch. First turn his Devastators moved up and I got my Seraphim+Repentance in engage range of them but also out of sight and the Mission managed to get into a firefight with some aggressive Ravenwing, winning and breaking them. The Retributors also got forward and put in some firepower against the broken Ravenwing downing another two and chasing them off behind some cover on the far right flank.
Second turn he went first and placed his Devastators on Overwatch alongside his still Overwatched scouts in response to the threat of my Engagement. I went for it anyway. Took 3 casualties on the way in but still beat the Devastators who withdrew into my half of the board, threatening my Blitz. It was numbers and attrition that was winning me the day over there. His second Devastators moved up and fired on the Seraphim, killing one and breaking the formation, who withdrew deep into his half in range to threaten his Blitz if they rallied. The Retributors swept in behind his Scouts, drew crossfire to the remaining Repentia and killed all four scout models leaving just the broken transports to flee.
Turn 3 The unbroken plasma cannon Devastators engaged the Repentia and killed them in a firefight. The Mission killed his Ravenwing with a second engagement claiming BTS and the Retributors spread out over th eboard to control his Blitz and second objective in his half and contest one of the objectives in my half.
Win Sisters 3-1 Dark Angels
Lessons: I think I understand why the Repentia have a 5+ save despite not having armour now. If they had no armour they would just die and lose practically every engagement, they would be a huge liability intermingling and as part of combined engagements and their lack of Firefight is an exploitable weakness making their MW attacks scarier on paper. I like them, they have their use and might be interesting with some Penitent Engines as a garrison.
Overall I had a lot of well armoured bodies on the board, good quality, well armoured mechanised infantry allowing me to trust in weight of numbers and armour to carry the day. Luck was not on my opponent's side however as he failed rallies several times through the game giving me the activation advantage (2 to 4 at one point).
The army felt good to use and very aggressive, my entire army was in his half of the board by end of turn 2 and stayed their for turn 3.
My second opponent (Rug on this board) watched the first game and built a list to try and demonstrate to the first player (a newer Epic:A player) some tips on how to use his Space Marines better. He took Ravenwing, Scouts, Land Speeder Typhoons and Devastators. Deployed almost everything scouted up forward and on overwatch. The range on his Typhoons meant that no matter where I went he would get to fire at me and cripple the Rhinos I rely on for speed and the concentration of his forces into a single column meant i couldn't deal with it piecemeal. The front line of skimmers meant the Repentia were not hugely useful.
I conceeded end of tun 2 when he was chasing the Retributors around with Land speeders and the Repentia were in the middle of the board with nothing they could fight after killing the scouts (Devastators were too far away to reach).
Now not everything was all that bad. I made two mistakes early on. 1. The objectives were deployed in essentially a column, allowing him the ease of concentrating his forces and leaving close to 3/4 of the width of the board unused during the game. I also deployed the Mission too far to the left, I should have swapped the position of the Repentia with the Mission and combined engaged with Seraphim+Retributors+Mission against the Ravenwing (or Ravenwing+Landspeeders who were intermingled).
Lessons: The Repentia have an easily exploitable weakness but can be a psychological tool. Dominions may perform their role better. The 'Faithful Slingshot' - Engage something with a formation that has gone faithful, lose, take few casualties (due to armour and fearless, avoid hits on the rhinos) and withdraw deep into the enemy half, remaining fearless makes them a tough proposition to get rid of likely requiring several formations and if not you've got a dangerous formation deep in your half.
Throughout there was some comment on the power and funky stuff you can do with Faithful, the large numbers and good amour but I don't feel either player felt things were too much. A proper Rhino Rush army could be very interesting to face.
Next time I might swap out the Repentia with either a set of Dominions or with some Exorcists and would put the Palatine into the Mission rather than with the Seraphim for more ablative wounds before getting to her. I d feel that MORE MISSIONS is likely to be a good thing.