As a frequent player of clerics in D&D, I'd like to see at the very minimum suggested domains for the deity selected, if not some form of restrictions.
A Trickery cleric of Tyr? This should not be possible imo.
Obviously this may be somewhat limiting with the current implementation of only three domains (sub-classes), but I imagine that additional ones will be implemented further down the development path. I would suggest it would make sense to select deity first, have their descriptions mention which domains are available to them, and then limit the sub-class options available.
If not having restrictions is a design choice for this game, then at least mention the suggested domains in the deity description.