A "new" route was added in 2005 which climbed GC til the second bolt then moved L and went up the narrow strip between GC and Extra G. A bolt was placed in the upper centre of the wall which was reachable from Extra G. This route is recorded in the New Routes book in Paddy Pallin.
Some time later it was noticed that (cruxy) holds on GC near the second bolt (where you would leave GC to do the new climb) were enhanced. Maybe this was associated with the new climb or maybe someone was finding the crux of GC a little too hard.
Around the same time the thumbpress/gaston above the first bolt on GC was lost due to natural attrition. I believe there's been some refashioning of the hold since but that seems more justifiable than the above (and it's still tougher than it used to be).
So you can still climb Extra G Connection and not feel too compromised!
But this chatter about the lower part of Muesli has me worried and I'll be having a look asap. Steve Kelly climbed a direct start to Extra G about 8 years ago, the thin line about half way between Muesli and GC. I think he called it Special K.
We should explain to Chockstoners that the Muesli Wall is probably the nicest and most popular little wall in the Adelaide Hills and there are 100s of climbers around here who would take a dim view of it being vandalised.