Yeah, exactly. There's a balancing act to perform, but randomness is not the key. Particularly in a game about combing skills to find successful strategies.
You should absolutely be able to pick all your skills. Because it's not picking the skills, it's knowing the right ones to pick and when and how to use them in battle. Atlus shouldn't need to hobble the player - that betrays a design failure on their part. Their job is to provide the tools; Yours is to figure out how to use them. They can't magically make you a good player and they restrict your potential to be one with silly choices like random skill inheritance and not being able to control party members. They're steadliy moving away from that stuff and I firmly believe they should.
Yes to the bolded.
Which is usually like 2 to 4 skills per combat, which, with the defautl skills of a demon, is
absolutely doable with the RNG fusions. The rest is having a balanced party to handle different situations. What you're describing is having a jack of all trades, who excels at everything.
SMT IV and P4G were such failures on the challenge point exactly because of this point: you could have one persona/demon with no weakness having access to the most powerfull magical spells, and one for the physical skills.
The goal of the press turn was to have you get a balanced party, with a variety of personas/demons covering different situations, not a couple one that could handle everything.
Planning all 8 skills is the "lazy" way through which you want to steamroll everything without having to change personas/demons. That, and the understandable wish to have OP demons/personas.
But from a balance point of view, you absolutely don't need to have free skill choice.