You're absolutely right, Sophie74656! It would have been interesting to follow their duel remotely, with an equivalent balance of power: both have a brilliant mind/powerful presence which make them strong leaders and with an armada of Borg Cubes for Seven and, a heavily armed fleet armada for Janeway ready to take orders, it could be epic .... AND
as bonus, we would get rid of Chakotay, who would have been killed or ... assimilated, what was one of his biggest fears! That is what it is to tempt fate, Chukkles!
In the same time, I can't imagine (and would never support the idea of) seeing Janeway and Seven kill each other in a direct confrontation or let some henchmen doing it for them, because their emotional attachment is too deep: it's the love between a (surrogate) mother and her (surrogate) child... even if in Endgame, there is relatively not much contact between Seven and the Capitain of Voyager.
It would be too sad to end a wonderful relationship like that ... unless Janeway and The Doctor manage to break AGAIN, the link with the Collective and help her to regain her life... What was made once, ....

-> Seriously, why our ideas of scripts seem better than those which were offered to us during the time of Voyager, in particular at the end of the 7th season?!