I don't really have too much to add to your concerns about the first part, i.e. an adventure that's basically on rails. If your adventurers are of the kind that will happily follow the rails, great! Otherwise, I favor your approach of putting out problems/situations that can be solved in different ways.
The play balance issue is more interesting to ponder. When you mentioned the bit about 'why would I use a Charm Monster spell that has little to no effect when I could take a super-buff', that got me thinking - what if you balanced it so they have around the same net effect?
Basically: if you can summon an elemental, that's a good comparison for being able to charm a monster. You should be able to charm a monster with about the same hit dice and power as a mage summoning an elemental at the same level. Or, if you could have cast a damaging spell with that choice, you should be able to compel the monster to do about that much damage against your enemies/their former allies before the spell breaks. It's a simple rule of thumb for how much benefit to let players get from clever use of their resources.
Similar argument for recruiting NPCs and taming pets: if you paid character points/picked spells/etc. for the purpose of doing so, your NPCs or pet should be about as useful as any other option you might have taken. In the case of your Unleashed character, maybe you'd have to park extra warbeasts because they get in each others' way or have dominance fights otherwise, but you paid points to be able to have at least one warbeast available.
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The play balance issue is more interesting to ponder. When you mentioned the bit about 'why would I use a Charm Monster spell that has little to no effect when I could take a super-buff', that got me thinking - what if you balanced it so they have around the same net effect?
Basically: if you can summon an elemental, that's a good comparison for being able to charm a monster. You should be able to charm a monster with about the same hit dice and power as a mage summoning an elemental at the same level. Or, if you could have cast a damaging spell with that choice, you should be able to compel the monster to do about that much damage against your enemies/their former allies before the spell breaks. It's a simple rule of thumb for how much benefit to let players get from clever use of their resources.
Similar argument for recruiting NPCs and taming pets: if you paid character points/picked spells/etc. for the purpose of doing so, your NPCs or pet should be about as useful as any other option you might have taken. In the case of your Unleashed character, maybe you'd have to park extra warbeasts because they get in each others' way or have dominance fights otherwise, but you paid points to be able to have at least one warbeast available.