Help us do what, exactly? Get past Toronto and Cleveland?
No rookie we pick is going to do that. So I take it you are in favor of trading for or signing a veteran, star player.
Not with that attitude!!! lol
Honestly though, I don't think any one rookie in this draft could improve us enough to be able to challenge Clevleand in a 7 game series.
However, if we add a rookie who can fill an important hole (e.g. Hield with his shooting/scoring ability or Poeltl with his defence and rebounding)
and then add another impact player via free agency or trades who can help us fill another big weakness or two (Dwight, Monroe, Horford, Butler, etc) then those two additions may well be enough to improve us to the point where we can really challenge Cleveland.
Remember that we gave an almost completely healthy #3 seed Atlanta Hawks team a pretty tough run without Bradley, without Olynyk, and with 30% of a Crowder. With those guys healthy, there's a good chance we beat Atlanta in that series.
Add a deadly shooter (who the defence must respect 24/7) and a consistently productive big man who can dominate the paint, and it pushes this team to a whole other level.
If our goal is to add least two guys who can improve our talent level and/or fill key voids...then we might have a better chance of doing that with a rookie and a good vet, then we do if finding two good vets.
At with the draft there are some guarantees - you know exactly who is available at your position, and you have full freedom to select who you want at that point. With trades and free agency there are no guarantees - you have no idea who is going to be available.
Trade and Free Agent markets are so heavily dependant on other parties. You don't get a free agent unless he decides you are the one team (out of 30) he most wants to go to. You don't get big name players in trades unless the other team happens to want what you are offering more than any other package being offered to them. That makes it very easy to come out of both Free Agency and the Trade market empty handed.
In the event hat the above happens (worst cse) the draft might be the only way for us to actually improve the team with talent.