A bit of an odd spin here.

First off, you've painted a singularly rosy picture of the post-Civil War comics landscape; you're ignoring the fact that the superheroes spent an inordinate amount of time chasing after one another. Worse still, the structure of the Initiative was easily compromised by the Skrull, and Stark's mistakes ultimately led to Norman Osborn taking power. Moving on to your examples, you point to the idea that government agents could have kept the Maximoff twins away from Dr. Banner. The twins beat all the rest of the Avengers (bar Hawkeye) before getting to Banner, and I fail to see how some agents would have helped. Likely they'd have been left firing at one another. It's true that Stark's 'Veronica' solution was flawed, but with the Avengers' main strategy - Black Widow - neutralised, Veronica was the only card Stark had to play. You've also stumbled into an awkward point when you argue the Hulk / Stark battle "would have ended a lot smoother had the U.S. government been involved" - really? I'm pretty sure everything would have gotten tangled up in red tape, with a diplomatic nightmare ensuing between Wakanda and the US. To be fair, though, it looks likely that the MCU equivalent of the SRA involves the UN, not the US. Your take on Ant-Man is an odd one. The precise point of the film is that Pym is unwilling to turn to the authorities, having been burned by them before (and we ultimately learn he was actually burned by Hydra agents within SHIELD). Pym has shelved the Ant-Man suit so as to prevent any government getting their hands on it, and an SRA-equivalent would be ignored by him. In fact, the Accords were being heavily discussed at the time, so Pym's actions were in full awareness of the international issue. That said, Pym and Lang also ensured everybody got out of PymTech before the building blew up. Your final example, the scepter, is utterly unpersuasive. We saw in The Avengers exactly what government types do with alien tech - they experiment on it. All that would have happened in that third scenario is a different disaster, where somebody else experimented with the Mind Gem, and caused something else. Incidentally, your argument about the Vision's being on Team Iron Man assumes too much. First, it assumes that someone who's smart is always necessarily right; second, it assumes that he's not a traitor to Team Iron Man (we know somebody switches sides at some point).