Question about Bard Instruments.

[Arrisard]

There are some hair splitting nuances about the specific question of capping 100% haste at level 60 as a bard (not to mention the various level haste caps from 1-60). Example, DotB is 55% and the highest haste item value a bard can get is 41% so you'd need to use Jonthan's Inspiration to actually cap.

But as to what I think you're effectively asking; no, haste items will not really be replaced by any kind of bard song/buff haste.