Yeah, I think you are on the right track. The main problem is Dwight Howard's willingness to re-sign with those lottery teams. I think Brooklyn is the only squad he green-lights a trade with.
What about Cleveland with Kyrie Irving, Varejao, Tristan Thompson (either as a player or as an asset who can be moved for a good player) and still additional cap space? They could go after Eric Gordon or perhaps split up that cap space and sign 2 of Ray Allen, OJ Mayo, Batum, Ilyasova, Ryan Anderson? Was Jamison happy enough there to come back cheap?
What about Minnesota and Portland, even though they are longer shots of landing the pick?
No, I don't think any of those are good enough to tempt Dwight.
Brooklyn has NYC and Deron Williams.
Top stars like Dwight Howard don't go and play with youngsters. They go and play with the established stars who has a long track record of success and is a proven playoff performer.
Deron Williams has the cachet that none of those other guys have. He has been a 20/10 threat for the past five years. Is proven playoff performer who has raised his game in the post-season. Led his team to four playoff trips including a Conference Finals appearance. Three time All-Star (who deserved more) and two time All-League (who deserved more) and a teammate of Dwight Howard's on Team USA. Deron Williams has a level of established excellence that none of those other big names offer.
Plus, Deron Williams is a point guard who gives Dwight that inside-outside threat that works so well, offers that dribble penetration that Howard's teams have lacked over the past few years and is an excellent overall complement to Dwight Howard's game + is a high assist player who has a rep for creating easy shots for his teammates + isn't a big enough name to overshadow Dwight (which seems to be a bonus for Dwight).
Kyrie Irving is a very good young player and a RoY but he has nowhere near the track record of Deron Williams at this early stage in his career. LaMarcus Aldridge just made his first All-Star game and saw his team flame out under his watch (as a recently appointed franchise guy). Kevin Love is a genuine force and carries a lot of respect after his performances these past two seasons. Still, not as much as Deron Williams and is a fellow big man and not a creative point guard.
Plus, Minnesota is the Siberia of the NBA landscape (most difficult place to tempt FAs to go to) with a questionable front office and ownership. Portland is a small-market that has a reputation for hurting player's endorsement revenues and an owner with a rep for interfering in basketball matters and hurting his team (and has just gone through 3 GMs in two years and recently fired his top notch Head Coach). Cleveland is also one of the least attractive cities in the NBA and most recently failed to win a title with LeBron James (the player who many argue is the best in the league and has been for the past 4 years).
Now, maybe if those teams had a stronger front office and ownership (say San Antonio) or if they had a history of winning titles, things could be different. But they don't ... and they aren't.
In summary, none of those offers are comparable to New Jersey chiefly because of Deron Williams (as star player and side-kick / complement to Dwight's interior game) and, to a lesser degree, the lure of NYC relative to those other markets (some of the least attractive markets in the league -- all of which matters to Dwight Howard).
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For any of those other teams to get in the mix for Dwight Howard, it would require a major addition prior to his arrival to convince him to commit to a contract extension.
Like you mentioned in your post - if Cleveland signed someone like Eric Gordon, that would be a difference maker. That could make Dwight Howard reconsider the Cavs. But that has to happen PRIOR to Dwight Howard joining to get him to commit to a contract extension.
Sort of like Ray Allen coming to Boston before KG was truly convinced this was the place to be.
Otherwise, they are trading Anthony Davis for a 12 month rental of Dwight Howard with no guarantee that he sticks around beyond that ... which nobody will do because Anthony Davis is too good to take that risk.