http://forum.c-rpg.net/index.php/topic,23607.msg341261.html#msg341261 now contains some analysis of damage types.
Simplified:
With about 60 base raw damage or more pierce > blunt > cut. Below that blunt > pierce > cut.
So people with low power strike should always prefer blunt over pierce if all other variables are the same. Blunt also does more damage when you get negative speed bonuses etc.
Difference between pierce and blunt is fairly small in all cases though. With very low raw damage blunt wins at considerable numbers proportionally, but the absolute damage is so very low that it hardly matters. At high raw damage pierce wins, but even at 100 raw damage it's just 7% more damage (31 average vs 29 average against 80 armor)
All in all if you could choose between equal stats weapon with blunt and pierce, blunt is slightly a better choice. Blunt weapons do have a knockdown generally though, which boosts them quite a lot.
If someone wants to take a look or play with it, here's the Excel spreadsheet I used:
http://nikita.tnnet.fi/~elmokki/crpg-damage.xls