I counted up the number of monsters of each type in encounters and dungeons, and it seems that Road to Legend leans towards Eldritch monsters, making them the #1 upgrade for almost all avatars, even if you have them at 30xp instead of 25. This was a little disconcerting, since I'm about to start a new game as Overlord and was looking at playing the Beastman Lord.
I'll probably still play him, but will have to think long and hard about upgrading humanoids to gold instead of eldritch (we're starting at silver since our last campaign ended just after moving into silver). It may still be worth it, though it'll depend on the spawns I can get with treachery. Legions of the Dead (4 normal and 2 master skeletons) is only 1 Treachery while Elite Beastman War Party (2 normal and 2 master beastmen) is 2. Though humanoids get a bigger boost going from silver to gold (command 2 and trickster 2 for starters).
The data includes:
- How many minions are in each encounter
- How many minions are in each dungeon
- How many minions the Farrows start with
- How many minions can be reinforced with a single expenditure in an encounter
It does not include
- Unquantifiable things such as the lower maneuverability of large monsters or the benefit of high speed on a ranged attacker
- Special abilities
- Average damage per monster type
- How many dungeons only offer a certain type of monster, or heavily favor one type even when they allow others.
I counted master minions as one and a half normal minions, since they've got increased damage and survivability, but aren't usually as good as 2 normal minions, since they lack multiple activations and don't double their other stats.
So, while it's not completely scientific, if you're just concerned with how many monsters you'll be affecting when you upgrade a category, go with eldritch every time unless you're ignoring dungeons (encounters and lieutenants favor beasts). Here's the results (the third column is always percentage, I accidentally left the headers off). The data is too big to upload here, but I submitted it to boardgamegeek's Road to Legend section, so hopefully it'll get approved. If you're interested, I can email it to you (it's an excel file, but I can export it to html or pdf if needed).