Doohickey (idler shaft lever) was upgraded by Kawasaki and released with 2008 models. While I know of no latter-day doohickey component failures, other forum members may have evidence of GENERATION 2 (2008-2013 production) doohickey malfunctions to share (including, hopefully, images).
Regardless, I think it's fair to say, Generation 2 OEM doohickeys are more durable and reliable by far than Generation 1 OEM doohickeys. The choice, whether to install a stronger, tighter-fitting aftermarket doohickey with extended adjustment range, is yours.
Spring tension issues have surfaced among Generation 2 KLR650s and bear watching, IMHO.
Don't know about Generation 2 subframe bolt strength.