Eubank might not have exceeded anyone's expectations vs Groves - but lets not forget he completely battered Spike.
Both are pointless mismatches and equally a waste of time IMO, it doesn't matter which is better when neither are good enough.
To be fair - anyone coming in on a months notice isn't going to stand much of a chance - unless it is someone already preparing another fight.
At least CEJ has a chin, good strength at Middleweight and to be fair GGG isn't the hardest to work out - just blooming strong and hits like a mule. Fully expect GGG to dominate CEJ, but I think it will be quite impressive if he can stop him.
Groves was dropping him, especially with having to make weight the more aggressive GGG would stop him, I have little doubt.