You answered your own question about why people are lukewarm on the off-season.
Kyrie has been injured every season since he left high school.
Love has a history of injuries (whether he finds them or they find him).
Andy hasn't had a healthy season since Lebron was here the first time.
Lebron needs more rest moving forward.
Yet all we have done this off-season is bring back Mo, who is one of the worst playoff performers in NBA history (and given Kyrie's health most likely will be thrust into a starting job at some point).
People are nervous about this off-season so far because on a team that relies so heavily on guys that are unreliable, their back-ups are awful freaking important. Little has been done in that regard.
You can go on hanging your hat on our record when healthy, but the rest of us in realityville (where we know that injuries will happen with this group) will keep waiting for reinforcements that don't leave us in the same position we were last year where Lebron has to almost kill himself to keep us competitive when the injuries inevitably come (and they will come).