Ainge has hit on very few draft picks in recent years. And by hit I mean someone that was drafted in a spot that would have gone appreciably higher in a redraft. Tatum is the only player drafted that I'd call a hit since Bradley in 2010 (obviously the last couple of drafts are up in the air still). That doesn't mean everyone else are busts i.e. players that were drafted too high, but his drafting record isn't what it once was when he had a much higher percentage of hits (Rondo and Jefferson being the biggest but even Perkins, Allen, Gomes, etc. were big time hits).
Ainge has seemingly fallen in love with the same type of player and he just hasn't been very good at drafting that type of player recently.
i am not quite sure how grant williams, romeo langford, edwards, TL, tatum, brown, yabusele, zizic, and semi are the same type of player.
for the post above, typically drafting in the mid to lower range does tend to produce a lot of misses for virtually every single GM in the nba. while mentioned is the fact that indeed in the later parts of the draft some gems emerge, the number of GMs who can find such gems on a consistent basis is very small.
but now let's look at rozier, a very good value at #16 in the draft. when looking at other players taken before rozier, not all players have done better than him. indeed, based upon performance, rozier would probably go sooner than#16 in a redo.https://www.basketball-reference.com/draft/NBA_2015.html
it is too early to judge the most recent draft, but so far GW, edwards, and waters might be players who would go earlier in a redraft. but then, ainge has hit on decent second round picks for a while.
lanford? not enough to judge yet.