A lot of my issues with the open world (other than how drab and generally lifeless it is) have been satiated the further I get, as the mission structure (including side ops) become more expansive and interesting, and I've mentally conditioned myself to stop treating the open world like any other open world, and instead mission specific sandboxes.
I think the key is to really invest in objectives and planning. It's important to play with the aim of completing missions and not just aimless shit, and I think it's equally important to try and immerse yourself in the mission itself and how you're going to tackle it. Like prior Metal Gear games I think if you want to play it the fastest, laziest way possible the experience probably won't be all that great; heavy combat headshot party with minimal complete objectives. But when you're on a mission and you're mentally investing in discovering and completing as many of the objectives as possible, looking for blueprints and prisoners, scouting for and extracting high value opponents, while also trying to stay quiet and undetected. That's when the thrill kicks in and the stealth is at its best the series has ever been.
I can still appreciate how fans of the prior games would be let down by the fact this is in many ways Peace Walker 2, with a very different pacing and presentation of the narrative. In that respect it would be unsatisfying. But deep down I'm stoked that Kojima/KojiPro's last Metal Gear, narrative aside, really doubled down on the game design and invested so much work into interesting stealth design that manages to hold its own over long stretches of play.
