The problem with Langford is how is he going to get playing time.
With Smart coming off the bench when all of the core 5 are healthy, Langford will not get significant playing for the next 3 seasons.
Gordon Hayward is not going anywhere any time soon.
Wanamaker won't be on the team next year and Romeo is already taking over Edwards minutes because those would have been his minutes if he wasn't injured. Smart gets Wanamaker's minutes as back up PG along with some shared minutes with Kemba and Romeo gets his minutes(minutes Edwards was getting) and the SG minutes Smart won't be getting because he is taking over Wanamaker's minutes.
Kemba 32 minutes
Jaylen 32 minutes
Tatum 32 minutes
Hayward 30 minutes
Smart 28 minutes
Romeo 20 minutes
Grant Williams 18 minutes
That's all of the minutes for positions 1-4. You figure 2 players at the 5 getting minutes, Timelord being one( and we will see who Danny has as a possible answer at the 5) and you have your 9 man rotation.
Of course due to injury, load management, foul trouble, poor play and slumps, garbage time, etc., other players, like Edwards or Waters or Semi or Green or the third string center(Tacko maybe) or the Memphis pick will get minutes. But there should be plenty of minutes for Romeo to play and develop.
And if Hayward opts out and signs elsewhere or gets traded for that center that you want so bad, Romeo's minutes and use will only increase. In my opinion, Romeo will have plenty of opportunity to play and develop this year and into the future.