Can you give me examples of what works wrong? I can't find any single issue.
Just try sending yourself 100million moto, for example.
(EDIT: I should also point out that the set of things that don't quite work right increases quite a bit if you do something like give yourself 100million coins on a testnet!)
Try to give yourself 100 million on Litecoin testnet and you will have the same issues, so what?
On ltc there will never be 100million coins, because the subsidy stops.
Further, it introduces some funny questions in protocol. Our network might currently accept a block of larger than the max block size (which could create all kinds of ancillary problems) as long as you're willing to pay an 84million coin transaction fee. If you want to send someone more than 84million coins, it is allowed but you can only do so if you pay an 84million coin tx fee in addition. (I'm not making this stuff up! Look at the control flow of GetMinFee, I LOLed.) Sure, these are problems that no-one would/could hit for a very very long time, but they are bugs to be fixed none the less.
I would recommend you to think about more immediate issue - year 2106 problem. But this is probably irrelevant because all current cryptocurrencies will be destroyed by quantum computers much sooner.
In terms of more immediate term needs, things like "work progress" are relative to this 84 mil cap number, so even today some tools which expect to see reasonable values for these rpc calls can't work with the reference daemon. Either some meaningful definitions for these things need to be established, or the "extra meaningless data" should be removed.
Can you be more specific, what are "these rpc calls"? I'm not an expert in all of the bitcoin rpc calls, which call depends on total supply? What "these things" except total supply are you talking about?