F-35 Lightning II offers stealth, advanced sensors, and multi-mission capabilities but lacks A-10's weapons capacity.
Also, if the F-35 does carry its full weapons capacity, it carries some on its wings, which makes it unstealthy.
The F-35 is fairly loud, and it carries a 25 mm cannon (with far fewer shells), so it may have some psychological effect.
I think it comes down to whether: the F-35's sensors can compensate for less time to "see" and attack targets; whether weapons capacity and loiter time matter; whether the F-35's speed makes it
significantly less vulnerable; whether the A-10's durability is
significantly better (it's more than "just" the titanium "bathtub", there are systems redundancies, the engine placement narrows the angles from which they can be hit, and the plane can land on the protruding wheel if the landing gear hydraulics fail; even the Projection Unit in the A-10A had a back-up aiming system in case of loss of main electrical power; the A-10 was designed for mission completion
and bringing the pilot home).