We all know that a Hardfork of BTC is not ideal, at best. But, Lets dig deep.

Currently the Bitcoin chain follows a signature that validates the blocks.

Q1 Does changing the Block-size change the signature,which is required to validate a new block?

If the anser is NO then what are we waiting for? Well it goes with out saying we need at least 90% on board for the HF to be considered clean...

Well why not opt for a 100% clean HF?

This is How I would do it...

Currently the miners indicates their votes for a certain BIP. (E.g. BIP 109). Now we all know that the miners are becoming more Dependant on fees, as time moves on. So jumping to 8MB is not economically effective,per say.

So?

Start with 2MB blocks then 4MB etc.

So that is the WE KNOW PART,Right?
So lets do the "You are the reason steem exists part"

I would let the voting for BIP 101 be viewed as an Upvote of the current block-size limit as per an inteval of 2,4,8,...MB.Hence. This would not cause the fees to drop to far and at the same time increases the Bitcoin networks Value.(Or we all could just migrate to DASH?) Lets move on.

If the votes of the next ,say 1512 out of 2016 blocks, are "up" the Lock-In occurs and at the 1008 block interval away from the last difficulty change(2016/2=1008) causes the increase to activate.Permanently.

This would happen time and time again.

The older nodes are "old" and can simply update .In with the new out with the old.
This does not mean,that wallets would become invalid. The contents did not change and the signatures did not change, nor did the validation process...

Because the signature did not change their is no other BTC than what is currently seen as BTC. If the signature changed it would be seen as an alt-coin.Maybe make "BTC-ZAR" or "BTC-EUR" and change the block-size limit to 32mb and with a different signature. The only difference would be the reputation,hashing power and how decentralized the network is.

You could reason that Bitcoin is the software and that in-it-self would give an perceived value.