you do realize in Avengers 1...
Hawkeye was only on screen for 12min
i expect spidey to only have a little less time than that. alot can be done in 10 min or less.. i think you're underestimating what screen time can and cant do.
they've DIRECTLY told us he's not playing a huge part... and thus far we only know of a chase scene... and a scene in peters room... there's absolutely no more proof than that.. and he was not in any of the big action on location pieces...
so i don't know what "proof" you are assuming... but you are going to be very very upset with this film the way you are setting yourself up.
This film is meant to be an intro for spidey and black panther.. but panther has always had the larger emphasis.. this is his intro more than it is spideys... and this film is STILL captain america's so the focus will still be on him... i don't expect most of the avengers outside of tasha, tony, and cap's team to have much screen time personally...
we even know tom's shooting schedules were not very long.... there's no way he has as much screen time as you seem to assume he does.
it's best to set yourself up to be happily surprised than to set yourself up to get your hopes up and then the rest of us posters who "told you so" have to listen to posters complain for the next several months about how they hated the film because spider-man had little screen time......