i doubt kishi threw that hint in for nothing, so yeah i fully expect naruto to combine sage and bijuu mode at one point. and it will be his ultimate form. he's already close to invulnerable, has massive speed, is the best sensor and has the best defensive mechanism in sage mode, in addition to awesome jumping abilities and frog take. combine that with ma and pa feeding him sage energy constantly meaning that he can stay in sm indefinitely, and his ability to enter sm much faster now. then add bm's close to unlimited chakra for a time, the bijuu dama, chakra arms, a chakra cloak capable of tanking pretty much anything, healing from the kyuubi's chakra. and the fact that the mode seems to be greater than the sum of it's parts given that naruto was immobilised by the deva path with the chakra rods from far away, and he was able to overpower nagato in close range with not even 1-tail's worth of kyuubi chakra.
in short what he would have:
best sensing abilities- chakra (sm) and malice (km)
best reaction ability (sm sensing ability), similar to the sharingan but faster, 360 and not dependent on eyesight (which can be an interesting technique combined with ma's dust techniques, hidden mist, smoke bombs etc)
best durability- can tank pretty much anything. naruto in km tanked the raikage's punches. naruto in sm shattered a stabbing chakra rod. combine those two
insane strength- naruto in sm can lift giant rocks. naruto in km can crush rocks with his chakra arms just trying to be gentle
best speed- no need to elaborate. can only get better
frog taka+ chakra arms- can give a new element to naruto's taijutsu
ma and pa's genjutsu, perhaps the best in the manga. and invulnerability to genjutsu, what with the kyuubi and ma and pa to break him out, plus his clones and speed.
healing abilities from the kyuubi
the kyuubi's life energy which affects the mokuton ( yet to be explained but i think it will be important).
in short, naruto would pretty much be a god
