Hi ctxpcs! Thanks for your bug report - I see now that if you start with minimum town development as wild and purchase either dwarves or satyr before pixies, the pixies are errantly excluded. This will be fixed.
I've been battling lag in battles just as well as I have been battling too many units giving a more chaotic and less interesting to follow and less possible to order around battle scene. I once did a poll, where the reserve system won out as the most popular option. The one about unit stacking was quite unpopular though it was my personal favourite. Reserves helped, but people often talk about the two other methods. Perhaps one of them will be called upon one day.
You are correct, Friars currently stand out at 66% winrate and will thus be continually nerfed until they fall in line.
Thank you for playing and for giving feedback! I hope you'll follow the development of the game as it continues on.