I have just such a MA/Nin stalker and I'd second that last post - crippling Axe kick is really quite powerful and if you plan on scrapping a bit then I think you'll like it.
I'm currently lvl 22 and made almost the same choices as you except I choose Cobra Strike for its disorienting effect which I like when scrapping - i.e. if you're fighting two people it stops you getting hit by one and ruining your AS after you placate another (BU, AS foe1, CAK foe2, Cobra foe2, Placate foe3, AS foe3, CAK/SK foe2 till dead) but i'm ALWAYS running low on stamina and now regret leaving it so late (I won't have it till 26 unless I respec). So you might want to think about Cobra Strike later on but get stamina asap.
I also took stealth for PVP though to be honest I haven't done much with it - BB always seems empty
so I could have left this till later I think.
I took Jump Kick instead of Combat jumping to get an extra attack - regret!! Just adds to the eating of my endurance and isn't very good (though maybe if I put more enhancements in it it would mak a difference).
And finally I didn't take Hasten - but this is just a personal choice based on a lack of knowledge lol
Superjumps great for hit'n'run which you'll often need to do when soloing.
All in all I love my stalker.. but look forward to a respec
