That first argument is the worst logic. I think everyone can see it. I pointed it out a lot to Airwings. If Justin Beiber got the role then he would have been the best for the role.

It mean nothing, and should not affect your decision.
Second, Asa being a better actor is your opinion. He could play a PP as good as Dylan, but I think as DR has said, it would be good if pp still had some humor.
Who know show old Spidey will get in the MCU? Either way spidey wont outgrow the role any faster than any other heroes.
SO I don't know where the whole 6 vs 4 movies came from, but that is inaccurate.
If Marvel casts Asa then I that means he displayed ALL of the traits required to play BOTH sides. Marvel knows what they're doing better than the fans do, end of story.
Civil War - Peter Parker age 15- Dylan O'Brien age 23
Solo 1- Peter Parker age 16- Dylan O'Brien age 24
Infinity War pt 1- Peter Parker age 17- Dylan O'Brien 25
Infinity War pt 2- Peter Parker age 18- Dylan O'Brien age 26
Solo 2-Peter Parker age 19- Dylan O'Brien age 27
Solo 3- Peter Parker age 20- Dylan O'Brien age 29
Solo 4- Peter Parker age 21- Dylan O'Brien age 31
Solo 5- Peter Parker age 22- Dylan O'Brien age 33
Solo 6- Peter Parker age 23- Dylan O'Brien age 35
Civil War - Peter Parker age 15- Asa Butterfield 18
Solo 1- Peter Parker age 16- Asa Butterfield 19
Infinity War pt 1- Peter Parker age 17- Asa Butterfield 20
Infinity War pt 2- Peter Parker age 18- Asa Butterfield 21
Solo 2-Peter Parker age 19- Asa Butterfield 22
Solo 3- Peter Parker age 20- Asa Butterfield 24
Solo 4- Peter Parker age 21- Asa Butterfield 26
Solo 5- Peter Parker age 22- Asa Butterfield 28
Solo 6- Peter Parker age 23- Asa Butterfield 30