The tourists beat Jos Buttler's hosts 2-1 in a three-match T20 series before dispatching Ireland in two short-format games in Bristol.
The competition for places ahead of the T20 World Cup, that kicks off in Australia in October, is especially hotting up in the batting department.
Opener Reeza Hendricks was in record-breaking form with four consecutive half-centuries in the absence of injured captain Temba Bavuma.
Rilee Rossouw made an impressive return to international cricket after close to six years in the wilderness while Tristan Stubbs showed he is a powerful hitter in the middle-order.
Aiden Markram is arguably South Africa's best T20 batter at the moment and David Miller, who led the team in the absence of Bavuma, is the most experienced member of the squad.
Speaking after beating Ireland by 44 runs on Friday, Boucher admitted there will be a few players hard done by when the final selection takes place for the showpiece tournament.
The Proteas mentor said: "There is great competition in the squad at the moment and in quite a few positions as well.
"We did give a couple of opportunities to guys to see what they can do, and they came good, which is great for us to see.
"I like that the guys are playing the brand of cricket we want to see and that's exciting. It's not maverick cricket, it's smart cricket, and our skill levels have been up. It can only be good for our squad if guys are challenging each other for spots.
"It's a good headache to have when there are so many guys vying for positions with a World Cup around the corner.
"I don't want to give out too much. That's strategy I wouldn't want to give away. I'm a part of a selection panel, and we've got some tough choices to make.
"I'm sure we will make those. There are a lot of guys competing and, unfortunately, we can only take 15 to the World Cup."
Boucher was especially pleased about the form of Hendricks, who showed impressive consistency after being on the fringes of the team for the last few years.
The 32-year-old right-handed batter notched up scores of 57 (33), 53 (32), 70 (50), 74 (53) and 42 (40) over the two series.
Boucher added: "Reeza has really come good on this tour. We've always known that Reeza can play, and he's been a fantastic player.
"I think it's just the way that he's gone about it with a touch of a different mindset and being a little bit more aggressive that has really stood out.
"He's a good player and he has stayed hungry. Four 50s in a row is doing something special in T20 cricket. I'm not sure how many people have done that."
Boucher and the Proteas will now turn their attention to the longest format of the game as they start preparations for a three-match Test series against England that gets underway at Lord's on 17 August.