Neutral game is situational depending on the character/player you are fighting. You improve that over time with experience and learning how each character works, but in general, yes its always good to work on your pokes/neutral game.
Your juggles were fine given the heights you had. At max height though you'd go for 7pk p+kppp, but it only works on medium/light characters. So basically Bayman and Bass you'd pretty much be stuck with pp6pk even at max height lol.
Hitomi's strings are far from linear. Thanks to the recent patch they made even more of her stuff track. I'd say one of the few advantages Hitomi has over a lot of the cast is the fact that you really cannot side step her...ever.
Pressuring with Hitomi is always a good thing, but it depends on who you are fighting. For the most part though, staying in your opponents face is easy with Hitomi as she can't really be side stepped, she's fairly safe compared to most of the cast, and being poked out is one of the least of her worries as she can just throw out a parry whenever she is at disadvantage.
As far as spacing goes, once you get the hang of whiff punishment you shouldn't be afraid of spacing anymore. Between 46p, 236p, 6f+k, 3f+k, 66f+k and 66k she has probably some of the best whiff punishment in the game. Next to being impossible to side stepping her, spacing is one of her other strong points that she excels at, especially for a striking character.
1p is situational. It's not as good as it was in DoA4, but it's still a very useful high crush. While it's unsafe on normal hit and on block, if it gets a counter hit it will cause a trip stun giving you some time to get back on your feet and put the pressure back onto them. 2p your options are just mix ups, but the reason its good is because on hit it leaves her at +1 frame advantage, which means everything comes out one frame faster. After 2p her jab comes out at 9 frames instead of 10, 6p or 6k comes out at 12 frames instead of 13 ect. It might not be much, but in a game where frame advantage is very limited, it helps a lot to let her continue pressuring your opponent.