Do it! Let the chips fall where they may.
Stop talking. Do.
You've been here long enough to know how Bitcoin works, there are no forked coins to trade only Bitcoin. And only Bitcoin on the longest chain is valid.
When small block cause Bitcoin to fork Bitcoin won't become an altcoin.
.
If there is a client coded which creates blocks that other clients do not accept as valid and there is mining being done using both clients, there will be a fork. If mining continues on both sides of the fork, both sides will continue exist. If you create a transaction with an input which is only valid on one chain and the rest of your coins, you will have coins on both chains. If someone is willing to trade other things of value for coins on both sides of the fork, there will be an exchange rate between the two.
I don't care which side of the fork gets the name Bitcoin and which side of the fork gets the name "random altcoin", I only care about the rules of the protocol.
I'm hoping that someone creates this client (which has happened) and starts mining on it without getting any percentage of consensus from other mines/users (which has not happened). If they are so sure of themselves, I don't understand why this hasn't happened yet. If you build it, they will come. Then we don't need to argue about the merits of small or large blocks anymore, we can simply vote with our wallet.
Because those running the show right now is the economic majority which means big market makers, those who sell the biggest amount of coins to the public. If they do a move, miners will follow, there is no doubt about that but these guys are being cautious and therefore slow to move. A bunch of them have settle December as a dead line back in August and now, as we approach this deadline and as the block are being full and the economic pressure is building up, Coinbase (which have received the largest investment) is now stepping up stating they will lead the move keeping the same deadline. It will happen, one must get prepared.