Y'all have an instamine reaction formation. You do realize people criticize monero as an instamine because its curve is too aggressive, don't you? The fact is, "instamine" will be thrown at you no matter what you do. The correct thing to do is what is best for the health of the coin and its economy in the long-term. Opinions on that may vary, but the instamine bugaboo has nothing to do with it. If you reduce emission rate, you will be giving more people the chance to participate in mining at favorable rates -- and that is the exact opposite of instamining. It will aid dispersion.
Having a longer mining horizon doesn't necessarily increase a future user's access to a coin. It increases a future miner's access to it. But in the long run, mining is dominated by professionals so this group diverges from the mainstream. Bitcoin and Litecoin are examples of this. An ordinary user is largely restricted to buying it on the market, which is available regardless of the emission curve. So the egalitarian aspect of the argument exists, but it plays out weakly in the real world.
The main reason you want a long mining horizon is so that you can have a blockchain that's secure without relying on tx fees. Of course, it merely delays the problem: the permanent fix is a minimum block reward, which MRO will have in some form.