I still like Chaos Theory the best, but I understand that the pace of movement as well as Sam's abilities need to evolve from that game. I understand that desire which drove Conviction and Blacklist. Part of the reason MGSV is so good is because of how much it expanded what Snake can do and how dyanmic his movement feels. It gave players a lot more options, and that's what matters in stealth games.
My issue with the newer Splinter Cell games though is the level design. Blacklist did have an emphasis on player choice but Chaos Theory oddly felt more immersive. I think it's because the levels in it felt more like "real" places that you could interact with. You spend most of Blacklist hopping around the geometry and sneaking behind chest-high walls like Nathan Drake. Chaos Theory's levels felt somewhat more intimate, letting you use the environment itself (lights, devices, computers, etc) to fool and get around enemies.
But you still did have a lot of shit to collect and outposts to clear out, having empty space between the interesting bits is not groundbreaking, (hello, Red Dead, Shadow of the Colossus), certainly not the way it was used in MGSV, where the world actively goes against the narrative. You never spot a single rebel in the open world actually rebelling against the military force. Yet they constantly harp on your actions helping them out. It's the quietest warzone ever.
In my opinion even MGSV's level design had somewhat of a better sense of place than Blacklist, though I'll admit for the most part Ground Zeroes had better level design than Phantom Pain, and my ideal third person stealth game would probably be more like the former but expanded into a full game.
Phantom Pain's problem with its open world is that very few of the missions actually take advantage of that open world. Most missions, especially side ops, take place in small areas that while themselves might be well-designed, don't really give the game much reason to be open-world. There are a few missions that encompass multiple enemy bases and the space between them and those can become pretty epic, but they're probably too few and far between. The individual main bases are well-designed and some are set on what are essentially linear paths linking open-ended areas. These actually remind me more of the original Crysis.
