See I am quite different on Pike. I was very emotionally connected with Pike and he resonates with me as someone who was facing a crisis and had to get through it. Mount's Pike strikes me as the logical outcome of Pike successfully overcoming his depression (because that's what it was in The Cage).
As for the rest, I have no issues with recasting. That's the nature of the business. I thought Pine and co. did amazing in recognizing that pitfall of that balancing act, as you note, avoiding pitfall, while still having a measure of original mannerisms.
My biggest question when people say "I don't see X person in the new actor" is what does that look like in an individual? For instance, I would say that I would look completely different to people due to a lot of changes that have happened to me in the last five years, much less ten. So, I always balance that expectation against the very real aspect of people growing in to a persona rather than always being that way.
It's sometimes why prequels can rub the wrong way is we expect these characters to be static rather than dynamic and capable of growth and change and development, and being wrong. There is such a fascinating expectation from audiences, myself included of what a character should be, because humans are not always so consistent.
