@franky1:
I proposed something similar to your idea to the Core-Dev mailing list last night:
https://bitco.in/forum/threads/gold-collapsing-bitcoin-up.16/page-266#post-9936
The email was rejected by the moderators and never went through. Here's what it said:
PROBLEM:
Bitcoin Core has committed to NOT raise the block size limit in 2016; however, significant support exists for an increase to 2 MB via the new implementation called Bitcoin Classic.
If Core sticks to its scaling roadmap, all nodes running Core would be forked from the network should blocks greater than 1 MB be accepted into the longest chain.
If Core deviates from its scaling roadmap--for example by capitulating and mirroring Classic's 2 MB limit--it may be seen as weak-minded and less relevant.
SOLUTION:
Stick to Core's Scaling Roadmap HOWEVER add an advanced configuration window to allow node operators to increase their block size limits at their own risk. This would allow current Core customers to track the longest proof-of-work chain (regardless of the success of Bitcoin Classic), while simultaneously allowing Core developers to continue to work on the scaling roadmap that they’ve committed to.