Restrictions aren't always a bad thing. If they eliminate too powerful options, the number of effective strategies actually increases. For example, you have 3 options costing 40,000 and 10 options costing 30,000. If you don't restrict the stronger options, you'll only have 3 effective strategies. But if you exclude them, you'll have 10 effective strategies.
In the standard setup, starting with a town at level 3 (Town Hall, Tavern, Fort), there's essentially only one effective strategy for Humans in terms of building a strong army: building tiers 1-5 of creatures + a basic Forge + a Stronghold. This is despite the fact that there are formally many options.
I don't understand why tying creatures to fortifications is a bad thing. Fortifications are one of the core branches of troop production. Their role is greater than in the original game because they support not only troop increases but also upgrades. In fact, with maximum development, a Castle or Stronghold will almost always be built for creatures because they are designed for that purpose. However, if the development is less aggressive (e.g., with a focus on economy or the Mage Guild), the role of fortifications in the first week decreases, and they may not need to be built.