I agree they should've that they should've added alien tech that would give them new capabilities, but I disagree with the whole "Patchwork" ship thing to the point it's some ugly mish-mash. The other Trek shows showed them as being better than that.
I mean hell, in Farscape they added new tech to Moya but it didn't change her appearance or anything.
A patchwork look gives a better impression of being forced to make do and improvise to survive. Voyager shouldn't have been operating like other trek shows, there should have been a more clear distinction between her situation and Enterprise D on an exploration cruise.
Can't comment on Farscape, never watched it.