I think Ben can be a very very good 3rd option. His movement is really good and quick, and I love his hustle and athleticism. I doubt he will ever be able to become a Kobe/Wade/Ginobili kind of player who can create his own offense at will, but maybe something along the lines of Rip Hamilton/Ray Allen should be within reach. Those players can be extremely effective when you pair them with someone who can create shots for them.
My knowledge of NBA history doesn't go that far back - have there been strong teams that consisted of a dominant big and a Ray Allen-like SG?
I can't speak to the good ole pre-3pt shooting days, but in the modern 3pt shot era? No actually. People routinely overrate shooters as an NBA force. You always need them, but a "star" shooter is often just a blown up roleplayer without help from his teammates.
BUT, if you wiggle a little and expand your definitions you can find several teams that came pretty close, including our own: Webber and Peja, who was a SF, but with the same can't dribble/off the ball movement that Ben will try to use I would think. Also the 90s Pacers teams, never truly great, but they had Smits in the middle and Reggie at SG and were perennial 50 win teams/borderline contenders.
Kareem never had anybody like that in the modern era, I am less familiar with his mid to late 70s teams (early 70s = Oscar, 80s+ I know).
Shaq never had anybody like that at any of his stops. his great guard wingmen were all attack the basket type superstar class guys. Penny, Kobe, Wade.
Hakeem had lots of shooters around him on his best 90s teams, but never anybody who the offense was going to waste a lot of energy setting up.
Admiral never had anybody like that.
Mourning never had anybody like that.
Daugherty never had anybody like that.
Trying to remember Andrew Toney's game, but don't think Moses had that guy either.
Yao never had anybody like that.
Dwight has never had anybody like that.
When I say they never had anybody like that, I don't mean they never had shooters around them -- having shooters is great. I was answering your question though if any of them had star shooters running around having their team set them up for tons of shots a game. Answer there is not as far as I can recall.
And actually, I'll be flat pissed if we start taking shots from Cousins to give to McLemore. But if Ben does nothing more than just stand dead still in the corner awaiting kickouts, and hits those kickouts when they come? That would be a huge step forward for the team after what we've seen in the first 6 games.