Wall of smaller drywall sheet pieces - tape or replace?
Every seam is a potential crack. 
Old drywall is more likely to have been hung with nails rather than screws, more opportunity to shift and pop nails. 
Taping is the hardest part of drywall work and bigger sheets means less taping (and less sanding and mess). 
Adding and removing paneling may have loosened the drywall underneath, exacerbating all of the above. 
Drywall is cheap, labor is expensive, and pulling down and rehanging may take less time that all that taping and patching.
Big pieces result in fewer butt joints (edges that are not tapered), which are harder to tape well. In a full sheet you have 16 feet of tapered joint and only 8 feet of butt. Smaller cut pieces often have butt joints on three or four sides. 
New drywall gives you an opportunity to use mildew/mold resistant material, if you are inclined.


I would start again.