Lonewolf, spot on chap.
Will the F-35 be a capable CAS platform? Yes, I have no personal doubt that it will! It is already performing well in the CAS environment, even with its limited number of cleared weapons. How can it move forward further? Well, expansion of weapon carriage types will eventually bestow a larger mixed-load capability that is the very essence of flexibility in most CAS regimes - think low collateral-to-big kaboom (scalable); cockpit-selectable effects; multi-spectral sensors, etc. That mixed load capability won't come early - most likely to be Blocks 4 and 5 so 2020-30. Wish it could be sooner but that's programmatics folks. You won't do it all stealthily of course. The weapon bays are fixed sizes and yes, the B variant has the smaller bay. The counter to that is that F-35 doesn't need to be the CAS master. She has a large array of other missions to fulfil. Most within the same sortie and all against threats that would make an A-10 pilot poop into his/her nice titanium bathtub. You talk survivability against direct hits. I challenge you that the A-10 is designed to take some direct hits because it is MUCH more likely to take one given its operating regime - i.e. in your face. So, the "spin" i'm reading above is apples-to-oranges, like so many other points made.
The A-10 doesn't kick the proverbial door down (access) and clean up the AOR for itself (airspace dominance). It waits for a massive package to do that job for it. 5th Gen platforms do (and will continue to) in relatively much smaller packages which is why we're investing in that future.
(yes, I wrote massive package.....)