Necromancers:
The undead are now lacking a way of spending 50K every match for a wizard, even though they have cheap players. Problem: they'll probably end up with a lot of spare money.
Why not:
Let the necromancer work also as a normal wizard. Say that he needs that 50K to gather ingredients and pay for tuition to be able to cast a spell during the match.
Alchemists:
Suck. They are in essence a lottery machine where you can win extra money - contrary to what normal wizards are: a hole where you can pour money in without the hole ever being filled.
Why not:
Follow the example of Warhammer FB, and let the dwarf teams hire the services of a local runesmith. Before every match, you can hire the smith to carve runes to the armours of your players. Simple list of a few runes with costs. Examples (the prices and effects should be considered carefully, these are just rough examples):
Rune of might: +1ST 50K
Rune of speed: +1MA 50K
Master Rune of speed: +2MA, sprint,sure feet 100K
Rune of dodging: dodge & side step 50K
You could buy a certain maximum of runes so that dwarves wouldn't spare their money for the final match and then have Rune of Might on each player or something

You'd have master runes and runes, and you could only buy one master rune per game, and several normal runes.
Sounds nice?
Wizards and Master Chefs:
IMO They are good the way they are now