Comment by AmericanChopper

Both of those comments are actually not great, but at least the first one has the benefit of being direct. Really the question you’re asking is something like ‘you’re deviating from an established design pattern here, why?’. It’s essential to communicate that you either don’t understand a decisions they’ve made, or that you have some particular reason to question a decision they’ve made. Beating around the bush dilutes that message, will usually just end up wasting time, and will often seem condescending. If your team can’t deal with good faith criticism in peer review, then you have a problem with your team culture, not a problem with improperly concealed criticism.