I think for the most part the team defense has been 'okay', it's definitely improved and we have KD to come back.
I think it's already proven that it can work, we've beaten up some of the leagues better teams, all without KD and for all his critics Kyrie has been completely unselfish (as has Harden). I don't know if we have enough to win it all due to lack of interior defense, which will be a problem against Philly/Lakers potentially, but at the same time - do you bet on a team outscoring us 4 times in 7 games? I'm not sure you do.