Gameplay Flow
Up front, I want to say that I think SF6 is a massive control game. Projectiles are incredibly strong, perhaps the strongest they've been in any SF game since ST, even though there are parries and no chip damage. It's because projectiles so clearly win the "drive war" over time while also building you super meter, but more than that, the properties of the projectiles themselves are very strong. Guile's sonic booms and sonic blade, Ryu's denjin fireballs, and even Luke's sand blasts are pretty wild for forcing blocks or forcing parry whiffs. The first time you're forced to block Ryu's EX denjin fireball, a laser beam from full screen that has sonic boom recovery, hits 3 times, and eats virtually all other projectiles along the way, you'll probably do a double take.
Remember, every time you block a projectile, whiff a parry on a projectile that doesn't come, or they fire one that's slower than you think forcing you to hold parry rather than tap it (or in Luke's case, dissipates in front of your face), you waste drive meter and put yourself at a drive deficit. And after 10 or so seconds of dealing with this, you could look up and see you've lost 2 drive. You'll have less control over the neutral, since now attempting a drive rush cancel puts you close to burnout, and you'll start feeling the heat and making mistakes, just like any other game with strong projectiles.
As a reminder, you cannot parry a projectile and then do drive rush immediately after as a way to close the gap. You have to wait for the parry stun to wear off (which would be equal to the block stun you'd suffer), and it would be basically no different than simply blocking the fireball and then doing reversal parry rush. Parrying a fireball is simply a way to hold your ground in a meter neutral way, and perhaps not get pushed back as much. It won't gain you any extra offensive advantage.
Perfect parry might be one of the keys to defeating fireballs; you won't freeze the screen, but you'll get a big paint splotch and you'll recover basically instantly, allowing you to walk through fireballs almost as if they aren't there. In theory you should be able to OS perfect parry attempts (and get regular block or regular parry if you're late/early), but I think it's harder to do this than it sounds because you will need to take advantage of your extra 20 or so frames granted by the perfect parry to probably walk forward. If you perfect parry and just stand there, you've gained nothing, so you might need to be holding forward while attempting one for it to be useful, or focus very hard on reacting to the visual cue. Not to mention, perfect parrying these projectiles of wildly differing speeds is going to be quite hard by itself, especially since you're also trying to watch out for beefy normals, jumps, and dashes.
Whiff punishing is also incredibly powerful, as anyone who's seen the beta can attest. Most pokes have hurtboxes that remain long after the active frames are over, and there are some juicy pokes in the game that can be canceled into drive rush, EX or super for massive combo starters and corner carry. This, coupled with rushdown being weaker, means that most offensive in this game will be started off whiff punishing or strong counter-poking.
Rushdown is weaker than many past SF games due to the lack of plus frames, as most characters have very few plus normals (some have none!). For some characters, if you block a non-drive rush medium normal at point blank, the offense appears to be effectively over; you can only stop mashing on jab by being far enough away to force a whiff, or perfect parry. The main way to stop people mashing on you in regular pressure is using chained jabs — your jabs are minus on block normally but chaining them allows you to create a frame trap — but this does not always lead to high damage even if it works.
Fortunately, if your second jab causes a counterhit, confirming with either with a third jab (or pre-emptively using a medium button expecting the counter-hit to work) is possible in SF6 and does not require insane reactions. I've definitely missed 3-hit confirms from SF4 and am glad to see them back. The only other way to get plus frames is via drive rush, which can be guaranteed if you want to spend 3 bars on a cancel, or is harder to set up if you only want to spend 1 (not counting oki).
But all this does mean that I think you have to really like smothering, stifling space control to like SF6's main pace of play. I think FGC history has proven that there are a lot of people that claim this is the game they want, but they actually hate it when they get it and are forced to play against true space control masters, because it's a very frustrating way to lose. Some people will like it of course, but I'm hoping that as the game develops or with new characters at launch or as DLC, the game has a nice mix of this style of play with other styles.
Personally, I tend to like games where you make good decisions during pressure equally as much as neutral, and whether SF6 will have that right mix for my personal preference is still unknown. It's my preference probably because I'm only an average whiff punisher, space control often leads to slow games where not much happens (hopefully drive impact helps the pace), and I equally value many other FG skills besides whiff punishing. I am hoping there will be some extremely creative rushdown characters that can apply offense in ways that are unique to others in the cast, and that don't just meaty with drive rush medium into a throw/counter-hit mixup, or jab into exactly and only another jab to trap mashing, which everyone in the cast can do. Maybe perfect parry will be the spice necessary to keep options open here, but because both offense and defense are in similar spots during these 0-on-block situations, it should be an equal resource to both players alike, rather than benefitting only the offense. I'm curious to see how this will play out.
I think the corner is particularly brutal in this game, which I like (don't get cornered!). You will quickly and easily lose control of your drive gauge, and if you're burned out, you'll be forced to do a difficult reaction with level 1 or level 3 super between a heavy normal canceled into drive impact, which does not have a big enough gap to jump or throw (I hope you saved super for this scenario, or else it seems to be truly checkmate). Also, you will get put in the corner much faster, since the first poke at 97 seconds of round 1 could be canceled into drive rush and corner carry, so you will see corner situations happen more often.
Throws seem both good and not so good at the same time. A lot of the potency of throws will really depend on the tech window, which seems to be rather large (I regret not labbing the exact window), which means delayed tech would be very powerful. It's especially powerful in games without many plus frames, since abare is strong in these games; it's hard to throw people who can tech late but also mash early. Plus, throw teching sends you almost full screen, so your pressure is over (they should not change this though, as letting you escape the corner on one throw tech seems important for this game), and throw whiff recovery is longer (they should also not change this).
That said, throw beats parry, which might end up being a very big deal. You might, for example, read a parry attempt with the 1 bar drive rush into throw, or at least into plus frames since parry does not change frame advantage and they can't act out of parry to stop you. And getting oki after a throw is valuable, although I don't think people need to be overly scared of throw loops in this game. There's no traditional stun, one correct decision gets you out (either throw tech or blocking a close-range medium), and I think shimmy will be harder due to larger throw ranges and more powerful lows for defenders to catch offensive players trying to walk back. You could still take some damage from multiple throws here and there, but that's the cost of losing neutral, so you should expect to take some damage on average.
I do think command throws will be quite powerful though (especially after drive rush where you can be +5 and frame trap the defender's jab with, say, an 8f command throw that cannot be teched). Only Jamie had a command grab in the beta, but the launch roster looks to have several more. I'm really interested to see how they attempt to balance command throws in this game. Maybe they will force you to spend EX to get powerful offense (which is a heavy cost after already spending meter on drive rush to force this mixup), and the regular command grabs won't be quite as scary? Jamie's regular grab was still pretty strong in the beta though, so time will tell.