Everything you said here just makes me more hopeful for Richard. Because like I mentioned before I realized it can go either way.
Off the bat it's clear that the Space stuff is all Rich. He dominates there. But even the earth stuff...Rich did a better job with that then Sam. However, even if that does not weigh in the decision you still can turn your reasoning, as on point that it may be in this case, on its head.
Example: Carol's being used in space more in the MCU may limit Rich's use in space in the MCU. However, Spiderman's use as the high school teen hero learning the ropes as well as a Ms. Marvel film that will do the same? Having another character in that role, who isn't even all that good at it, may be a little much. Giving Rich more of a shot.
Anyway, you turn it there is a fight for the other character. Only difference being Rich's stories are admittedly better and it seems that Rich was more well loved than the other character. My only hope is that when it comes time to make the final call "the powers at be" will make the discussion based on quality and fan dedication.
Like I said before Sam Alexander as a character will live on regardless. If Richard Rider isn't the star of the Nova movie it will be a death sentence just based on how Marvel is currently run.
In short I'm going to keep my fingers crossed and do my part to support Rich until then.