Here is some mathhammer on the average results for a unit of 3 rippers based on the following conditions:
1) The standard calculation = Probability of hitting x probability of wounding x probability of failed armour save x average number of attacks
2) The average roll will be used so any d3 = 2 (i.e. for hand of glory or beefed up frenzy)
3) Case 1 is a typical elf archer unit of 20 models
4) Case 2 is a typical High Elf spear unit of 20 models & an assassination run over the front (i.e. rippers are arranged so that two models touch the wizard and the 3rd model essentially provides for casualties without losing attacks on wizard).
Case 1A (flank charge vs Unit of 20 x T3/S3/WS4 troops - i.e. typical elf archer unit, unit PASSES fear check)
Riders = 3/6 x 4/6 x 6/6 x 3 = 1
Rippers = 3/6 x 4/6 x 6/6 x 9 = 3
Stomp = 6/6 x 4/6 x 6/6 x 2 = 1.3
total CR = 5.3 + flank + charge = 7.3
Wounds taken = 4/6 x 3/6 x 3/6 x 2 = 0.3
End Result = Rippers win by 7 less standard & rank = 5
Case 1B (flank charge vs Unit of 20 x T3/S3/WS4 troops. Unit subject to Toad Rage, Unit PASSES fear check)
Riders = 3/6 x 4/6 x 6/6 x 3 = 1
Rippers = 3/4 x 4/6 x 6/6 x 15 = 7.5 [to hit = 1 - chance of missing = 1 - (3/6 x 3/6) = 3/4 ]
Stomp = 6/6 x 4/6 x 6/6 x 2 = 1.3
total wounds = 9.8 + flank + charge = 11.8
Wounds taken = 4/6 x 3/6 x 3/6 x 2 = 0.3
End Result = Rippers win by 11.5 less standard = 10
Case 1C (flank charge vs Unit of 20 x T3/S3/WS4 troops. Unit subject to Toad Rage, Rippers get Hand of Glory, Unit PASSES fear check)
Riders = 4/6 x 4/6 x 6/6 x 3 = 1.3
Rippers = 8/9 x 4/6 x 6/6 x 15 = 8.9
Stomp = 6/6 x 4/6 x 6/6 x 2 = 1.3
total wounds = 11.5 + flank + charge = 13.5
Wounds taken = 4/6 x 3/6 x 3/6 x 2 = 0.3
End Result = Rippers win by 13 less standard = 12
Case 1D (flank charge vs Unit of 20 x T3/S3/WS4 troops. Unit subject to Toad Rage, Rippers get Hand of Glory & Wyssan's Wildform, Unit PASSES fear check)
Riders = 4/6 x 5/6 x 6/6 x 3 = 1.7
Rippers = 8/9 x 5/6 x 6/6 x 15 = 11.1
Stomp = 6/6 x 5/6 x 6/6 x 2 = 1.7
total wounds = 14.5 + flank + charge = 16.5
Wounds taken = 4/6 x 3/6 x 3/6 x 2 = 0.3
End Result = Rippers win by 16 less standard = 15
Case 2A - Assassination run vs HE spears, all attacks directed on wizard. HE pass fear. Essentially this is worst case.
Wounds taken = 8/9 x 3/6 x 3/6 x 20 = 4.4 (two rippers die due to ASF re-rolls and the martial prowess allowing all 20 spears to attack).
Rider = 3/6 x 4/6 x 6/6 x 1 = 0.3
Rippers = 3/6 x 4/6 x 6/6 x 3 = 1.0
Stomp = 6/6 x 4/6 x 5/6 x 1 = 0.5
Result - Rippers lose by ~4 and flee but wizard wounded.
Recommendation - only use this suicide run if the wizard is a already wounded.
Case 2B - Assassination run vs HE spears as per 2A but toad rage in effect.
Wounds taken = 8/9 x 3/6 x 3/6 x 20 = 4.4 (two rippers die)
Rider = 3/6 x 4/6 x 6/6 x 1 = 0.3
Rippers = 3/4 x 4/6 x 6/6 x 5 = 2.5
Stomp = 6/6 x 4/6 x 5/6 x 1 = 0.5
Result - Rippers lose by ~3 and flee but wizard is killed. Rippers likely escape pursuit and no VP surrendered. Clear win for lizzies but Rippers are done for the game.
Recommendation - A good exchange and if the pursuit path is set up with a lizzie unit that will crush the HE, all the better.
Case 2C - Assassination run vs HE spears as per 2A. Toad Rage & Hand of Glory in effect for WS 4&5/I6&5.
Wounds taken = 3/6 x 3/6 x 3/6 x 20 = 2.5 (one ripper dies due to ASF. HE re-rolls lost as riders now I6)
Rider = 3/6 x 4/6 x 6/6 x 2 = 0.7
Rippers = 8/9 x 4/6 x 6/6 x 10 = 5.9
Stomp = 6/6 x 4/6 x 5/6 x 2 = 0.5
Result - Since the riders and rippers have different initiatives, it will be possible to split the total ripper attacks based on whether or not the riders inflict a wound on the wizard. Even a wizard lord (without ward save) will most certainly be killed if all attacks are directed against them while a 4+ ward will result in a dead wizard lord on average if all attacks are put against them.
Recommendation - A lizzie victory as even a wizard lord with ward save is taken out. The possibility of winning combat by ~1 also exists if the ripper attacks are split evenly on unit/wizard based on rider results needing only one wound left to kill the wizard. This must be balanced against the importance of taking out the wizard since that is the main goal of the frontal assault.
Case 2D - Assassination run vs HE spears as per 2A. Toad Rage, Hand of Glory & Wyssan's in effect for Rippers.
Wounds taken = 3/6 x 2/6 x 3/6 x 20 = 1.7 (one ripper dies due to ASF. HE re-rolls lost as riders now I6)
Rider = 3/6 x 5/6 x 6/6 x 2 = 0.9
Rippers = 8/9 x 5/6 x 6/6 x 10 = 7.4
Stomp = 6/6 x 5/6 x 6/6 x 2 = 1.7
Result - Very similar to 2C but the impact of wyssan's reduces damage and increases casualties inflicted.
Recommendation - A lizzie victory as the wizard lord will certainly be killed unless the dice totally abandon the rippers. The possibility of winning combat overall by splitting attacks is even greater as the rippers have greater damage potential with wyssan's. Again, key factor in allocating attacks will be the importance of killing the wizard.
Hopefully, this info will provide useful to others in deciding how to employ rippers. They have definite potential for swinging the magic phase through assassination & Toad Rage. Rippers can lay a severe beating on T3/S3 troops with and without magical buffs but Toad Rage appears to be the biggest factor overall.