A table featuring defense information for each player in the league based on selected filters.
www.nba.com
I have no idea where you are getting Ayton is the better defender. Capela is 48th in defensive rating and 19th in defensive w/s while Ayton is nowhere in Top 50 in defensive rating and is 40th in defensive w/s. Also, Capela is a much better shot blocker which Ayton should be ashamed of given his size and athletic ability.
Ayton is a much better offensive player no doubt but the problem is an unmotivated Ayton is not an offensive threat, he is too comfortable deferring shots to his teammates which we've seen since he's been in the NBA, he is extremely passive.
Collins maybe in a slump this year but my point is what is PHX getting from Crowder sitting at home and Saric barely playing that Collins wouldn't be considered an upgrade? Craig and Johnson aren't suited to play PF full time and would solidify bench with Landale, Biyombo, Lee, Payne and Okogie.
Defense as a whole has been bad but front court seems to be getting exploited by lack of length.