Accessory tinkers only become available when:
A: Item A is a good item but is now starting to fall off in efficiency compared to other things, in which case Item B brings it back to relevancy (Most notable example being Feral Claws into Mechanical glove)
B: Item A is not good enough on its own, in which case Item B gives it the little something it needs (Pretty much what Yoyo bag does when it gives the extra range from the String to the Yoyo Glove, and the thing Frog Leg needs).
C: Both Item A and B are terrible and the combination tries to make a good from two bads (most of the time, you still get a bad anyways)
Regardless of how useful you find the dash to be, you can't just combine it with another noticeably impactful mobility item when neither of the two need a buff that massive.
It would be like thinking the Frozen Turtle Shell needs a buff (it does, but much like the Fleg it just needs a bit more), so you slap the entire Worm Scarf to it. There is simply no way to balance that without nerfing one of the two effects to the point where the new thing barely becomes an upgrade. If you find an item combination to be so strong that the effects need to be toned down, then chances are those two items are better off not being together.