Where are you getting those numbers?
I've only found Nowitzki's wingspan mentioned as 7' 1" or 7' 2" (and only as passing reference in articles on nbadraft.net).
Some of them are difficult to find, but if you search hard enough they are out there.
I thought I had read at one point that Dirk had a 7'5" wingspan, I might have been mistaken on that one.
The others I listed all legit though, and you cannot even begin to compare Bender to Dirk because Dirk was about 50x better then Bender when he was entering the NBA.
There is actually an interview with Charles Barley in which he talks about the first time he saw Dirk play as a member of the dream team. Apparently the Dream Team played an exhibition / practice game against Germany before Dirk came to the NBA, and Dirk absolutely destroyed to the tune of something like 40+ points. The US guys apparently were completely dumbdounded and didn't know what hit them, and Chuck said his final thought was "this guy is going to be amazing".
Bender right now is not that guy.
It might be a bit more instructive to go look up the pre-draft measurements of more similar physical players, such as Tyson Chandler, Kevin Garnett, Chris Bosch, Anthony Davis, Marcus Camby, Dikembe Mutombo, Pau Gasol, etc. If I recall, all of those guys weighed in between 214 and 227 lbs pre-draft. KG was also 18, but I think the rest were 19 or 20 when drafted.
I am aware of the measurements of those guys.
Kevin Garnett, Anthony Davis and Paul Gasol all had elite length (~7'5" wingspan). Davis and Garnett also added elite athleticism to that. I believe Camby's wingspan was also somewhere in the 7'5 range. I haven't checked Mutombo, but I'd guess he would be around that range too.
Chris Bosh's wingspan was 7' 3.5", he was an excellent rebounder early in his career, and he was always a far better offensive player then Bender is.
Chandler is really the only guy on that list who had so-so length (I think around 7'1" or 7'2" wingspan from memory) and he has only managed something like 3-4 impressive seasons as a good defensive role player - something I'm confident Bender could also become, but not something I'd wager a #3 pick on.
The question about Dirk wasn't to compare Bender's overall talent, but because your wingspan measurement doesn't match up with anything I've ever found about him. I also know of no official wingspan measurement of KG, though I would be surprised if it wasn't on the order of 7' 5".
I don't know the date of when Barkley first saw Dirk, but it's important to compare similar ages. When Dirk was 16-18, DJK Wurzburg was still in second division status so the level of competition was lower. He dominated, of course, but so has Bender when against lower level competition. Dirk didn't come to the NBA until he was 20. Like many rookies, Dirk's first year in the NBA was pretty modest.
Here is the main point of my question:
KG was 214 lbs at age 18. Bosh was 226. Chandler 224. Camby was 223 coming out of college as a senior at age 22. Dikembe was 228 as a 25 year old.
The point of this is not that Bender is destined to be one of those greats, but that there is no reason to freak out over Bender's weight at his current age and proclamations of whether he will be able to bang with NBA centers weighing 240-260 lbs seem rather silly at this time.
Bender was measured at 7' 0.5" w/shoes, 7' 2" wingspan and a 9' 3" standing reach almost exactly a year ago at age 17. He weighed 216 lbs though is currently listed at 225. I don't know how you are assessing his 'average athleticism' and 'average talent'. We don't really have a current measure of his athleticism other than the eye test which shows him to be at least 'quick on his feet', fwiw. As for talent, he has a far better outside shot than most of the bigs we've been talking about had at his age (or ever) and he gets routinely lauded for such 'skill' aspects of his game such as passing, court awareness and defensive fundamentals. Whether that is 'elite' is hard to gauge. When he's been up against same-or-slightly-older competition (Juniors, U18), he has dominated. That doesn't sound average.
His wingspan may not be elite, but it isn't below average by any means, and his 9' 3" standing reach is better than many of the bigs you've been talking about. It is particularly notable considering his expected role as a outside-in based offensive player. And again, that measurement is a year old, when he was just 17.
I'm going to focus on just one of the comps, since I don't have much free time at the moment.
Chandler was measured at age 18 1/2 at the same height and as having 7' 3" wingspan, his standing reach came in at 9' 2". He weighed 224 lbs. He was just 1 month older than Bender will be at the time of his draft. Chandler was a #2 pick. He was arguably just as valuable as Dirk to the Mavs title team, DPOY the following year, an All Star and a multi-year All-Defensive team member. I think he was probably worth that #2 pick.
Here is Chandler's scouting report on defense from DE after 6 years in the NBA:
A tremendous defensive presence due to his mix of length and athleticism. Has the quickness to defend the high post and challenge shots from the weakside. Shows good timing when blocking shots, and has improved his one-on-one defense. Doesn’t block as many shots as you might think, but plays very good defense regardless. Still commits some questionable fouls, but is vastly improved in that department. Does a great job boxing out and exploding to the ball to grab rebounds. Can hedge the pick and roll. Will change his fair share of shots and carry the load on the glass.
That reads very much like the scouting reports on Bender's defense: A slender, quick-footed high-paint defender with great fundamentals who can switch/hedge on the pick & roll and is a good weak-side shot contester. Bender actually blocks a lot of shots. In same-age competition, he has had huge rebounding games.
The difference in their scouting reports shows up on the offensive side where Chandler was (and still is) considered an average offensive player without an outside game while Bender is considered a plus offensive player with a very good outside shot, a great handle for a 7 footer and above-average passing skills.
There is no guarantee that Bender will be worth the #3 pick, but I see nothing in his physical measurements that suggests he won't.
Also consider the hypothetical, gedanken experiment: What if Bender had spent this last year (age 17-18) in a US Prep school program? He would have almost certainly dominated like nobody's business. Heck at age 16 he dominated at the U18 European Championships, against older players who are in or soon will be in the NBA.
The current kid ranked #1 on DraftExpress' early 2017 mock draft is Harry Giles, who is 5 months younger than Bender is right now. He was just measured at the recent (a year older than Bender at his last measurements) Hoop Camp at 6' 10.75", 222 lb, 7' 3" wingspan and a 9' 1" standing reach. His scouting report reads like a similar list of defensive strengths (great perimeter defense, quickness and fundamentals) and similar ability to get up and down the floor. But no outside shot and nowhere near the ball handling skills that Bender has.
My speculation is that Bender would easily be pushing Giles for that #1 spot on that board, if he were in a US Prep system and coming out next year.
Now, does that mean he should be considered worth the #3 pick in THIS year's draft? If all we care about is ceiling, then I think yes, without question. If we care about how soon they might reach that ceiling, maybe not.
But before the forced one-and-done system, he'd be a no-brainer top draftee out of high school, just like players like KG & Chandler. And he's been playing in a FAR more competitive league this last year than any high school.