@James - you are still missing the point which is that WordPress users have had a change forced upon them that is (apparently, as neither you or anyone else seem to have indicated otherwise) not safely reversible.
That change means that the workflow used by people making their living by developing WordPress sites for clients is broken when the development site (with no warning whatsoever) has the database changed (because WordPress considers the conditions to be right on _that_ server) and then the site developer tries to migrate the site to their clients hosting that _does not_ support the database changes in charset/collation and they cannot deliver the site to the client.
Now you can argue until you are blue in the face that all hosts should be on up to date versions of X and Y and Z but, you know what, as I previously stated above, the real world simply doesn't match such a cosy idealisation as hosts don't; all have up to date X and Y and Z and not all clients could give a fig, they just want their site delivered.
Your arguments are simply meaningless because they simply based on how you think the world should be but the world just isn't like that, however much we might all wish it were.
So I say to you again, why don't you get in contact with all the thousands of hosts out there and tell them they really ought to update their "stuff" because you say they should.
And, as I keep saying, WordPress didn't force you to use a higher version of MySQL.
You just don't get it do you - if the server you are on has the right conditions WordPress forces an update to the table charset/collation when the update to 4.2 is made doesn't it, you cannot possibly deny that that update is forced, the user has _no_ choice, it happens automatically.
From that point on you are _forced_ to use the higher version of MySQL if you want to migrate that site to another server/hosting using the site migration processes that thousands of WordPress users would use and have used for ages. How is that not WordPress forcing you into using a higher version of MySQL? Any information I have seen from WordPress so far says the database "upgrade" is a one-way operation, it cannot be safely undone which means you cannot go to a server/hosting that has an earlier version of MySQL - but according to WordPress requirements all you need is MySQL version 5.0.
So again, all your "ideal world" arguments simply don't hold water in the real world but it's good to know that you are not really interested in the problem, in fact you refuse to even acknowledge there is a problem which is very sad.
Oh, and you strangely never responded to the point about this database upgrade being made optional through an "opt-in" check-box or similar. The information from WordPress make sit clear that it can be done at any time, it doesn't have to be done as an automatic thing on a version update so a simple checkbox to select and save and have the upgrade done if you wanted it would have done the job with no fuss, no mess.
Perhaps you would care to answer how many users actually _need_ this database upgrade and how many might _want_ it and how many would really rather not because of the implications?
Remember, just because you have a problem, or even a handful other people do, doesn't mean that everyone else does.
Hmm, did I say that "everyone" has a problem, no I didn't. I have specifically outlined the scenario that will result in some unknown number of people having a problem - but given the huge user base of WordPress do you really think it will be just a "handful", but at least I seem to care about their problem - you apparently do not because it may only be a "handful" of people. But of course you have no way of knowing that either do you?
If your hosts insists on using a version of MySQL over 5 years old, I fail to see how that's a WordPress problem.
And again, if it is a version of MySQL that WordPress states is supported and yet a WordPress site cannot be migrated to that host because WordPress made the site incompatible with that host then it _is_ a WordPress problem.
Look at the WordPress requirements page - there is no warning that using a server with MySQL 5.5 or greater will then render your site unmigrateable to a host that supports only an earlier version of MySQL that is all that WordPress claims to require.
I appreciate you are just a volunteer and doing this in your free time but that doesn't give you the right to be judge and jury over what is or isn't a problem:
I'm not one of the developers, and I personally don't see this as that big of an issue
As I say before, it isn't about what you "personally" think and as you have stated you are not one of the developers so are you really qualified to judge what is and isn't a problem for all those workaday site developers out there trying to make a living using WordPress? No, your role is to help people where you can and if there is something that you are not sure about or qualified to judge then you refer it on to someone who is - that is support. I'm used to this "blocking" from host supports on bad hosts whose sole job is to simply deny everything and blame someone else - I had hoped for something better here.
I honestly see no point in continuing this conversation as you have obviously decided that as you don't think there is a problem then there isn't one - I wonder what it is like to be so omniscient?
Good luck with your future endeavours.