Call me an capitalist pig who's trying to exploit poor miners and ask for a little more than just security
I won't call you a capitalist. A capitalist would believe the free market can solve the "issue" (which is really a non-issue as your transaction was likely delay for completely different reasons).
No problem here, let's increase fees. I think I said it at least 10 times already.
Who is stopping you? Increase you fees. That is how a free market works. If you are concerned about this increase your fees 10 fold. Get a couple thousand other users to do the same thing. With higher fees there is more of an incentive to include transactions.
What I'm not comfortable with it the "unlikely" and "tiny fraction" parts. Luke proved that it can happen. How can we make sure it's not possible in the future, to Bitcoin? Everyone disagrees with my idea - which is all right, that's why this is a forum.
You are aware that Luke is a small fraction of BITCOIN but was >51% of the altchain which was attacked. It IS impossible in Bitcoin without 51% of hashing power AND ... DRUMROLL .... if someone has 51% of hashing power they can do a lot worse things than not include your transaction.
I don't see a better idea yet, but I'm hoping the great masters of the Bitcoin will find one (most likely annoyed by me, lol).
Why would there need to be a solution to a non-problem? You haven't even proven a problem exists. Most miners include transactions. As block reward continue to decline towards zero and fees rise the economic pressure will make the % of network that excludes transactions fall to nothing. You don't need 100% of the network working on your transaction for the network to work.
How many empty blocks have you seen in last week? How many of them were empty simply because there were no transaction during that period of time?
It is entirely possible that some % of network isn't even aware of your transaction. Even if they are there is no mechanism to guarantee the time the transaction was created. Even if there was different parts of the network would have different timestamps for the same transaction. That is even before issues like a network split, intentional attack, abuse by pools (pools could cripple smaller pools by paying a fee to have people run clients which only forward transactions to them).
My prediction. No "solution" for your non-problem will ever be implemented because a) no problem exists and b) the complexity and risk of unintended consequences would far outweigh the benefit.