I think Naruto has a whole bunch of mixed feelings when it comes to pursuing Sakura, in fact I think one of the main reasons I was OK with the relationship even when I was against NS (and any romance for Sakura because I didn't trust Kishi to allow a female to be in a relationship and still hold her individuality), is because it gave Naruto a really easy to read, straightforward guy layers. He's willing to put Sakura's feelings, dreams, and goals above his own; that's quite meaningful when considering Naruto is the guy who never gives up, the guy who's totally focused on his goals, the guy who once upon a time only had his goals to hang onto (didn't have people to hang onto). What Sakura brings out in him, is quite amazing.
The thing about his calling her his gilfriend (or really, his "girl" or his "her") is that he wasn't really saying "yes, she's my girlfriend," because that would be inaccurate, he knows that their relationship is unresolved (he never answered her when she asked him). Rather --and this is just my interpretation-- I felt that he's saying "yeah, she's basically my girl, she's the girl who I see as my girlfriend." Naruto's really focused, he's really loyal, he'll love Sakura and only Sakura even if she started up a relationship with someone else forever or at least until/unless he confesses and is rejected (a straight up rejection might allow him to move on to some extent). Sakura is his girl, she's the only person he can envision as his girlfriend (for the time being anyway), at least that's how he saw it (and I'm not saying that through his loyalty he wouldn't have fun with anyone else in manga canon, after traveling with Jiraiya for years --Jiraiya who had the same extreme loyalty to Tsunde but still had his fun-- as per my head canon Naruto isn't as...innocent...as some others might feel haha).
Oh man, I do hopey you're right. I miss seeing her kick ass.
I wouldn't be surprised if Sakura used herself to shield Naruto at some point. Remember, chances are she can at least survive being bisected (what better way to show she has surpassed Tsunade than showing her bisected or worse, but better able to heal herself), so she could survive (while also having Naruto freak out for a bit because he doesn't know that she can survive), and it'll also bring closure to Chiyo's advice to Sakura, to place her life in danger for someone better deserving (than Chiyo herself).
Honestly, after the blatant OR-NS parallel recently (the one with Minato's flashback of when he talked Obito, how similar it was to the Naruto-Sai panels), I'd be surprised if NS wasn't used somehow to TnJ Obito.
About the bolded, I'm one of those ones that likes to think of Naruto more innocently than that. Maybe I'm old fashioned that way, but when I think about loyalty in love that includes the sexual too. And yeah, Jiriaya loved Tsunade and still 'had his fun', but he's Jiraiya...
To each their own I suppose.