It appears that almost all coin chains are to some degree a pre mined, either by ignorance of the project, or lack of understanding at the time, access to hardware, or obscure tactics.
BTC for example had a defacto premine. Not many people new about it at the start, and even then, many who did did not understand it. Further it was (and still is) a huge risk. Eg Satoshi and early adopters could have wasted there collective time. Yet they mined away...probably at a large loss.....at the time. I am not casting this as wrong or bad, rather probally well deserved due to the risk of what they were spending their time on. The issue is now however its hard to price in the risk to the chain, as we do not know clearly how many BTC's are tied to one entity.
It may be that all coins even if a coin is announced weeks in advance and *not premined* are still subject to a relatively select few to mine, or defacto premine.
Look at the BTE, FC, TRC,LTC who but the first on the chains really had it easy as a function was this chance/risk access to hardware.
In fact it maybe that a known premine, eg IXCoin or NovaCoin may provide a form of stability, with the certainty that there was an amount secured by one entity and being able to price in that risk, rather than believe that it was not premined when in reality it was just in stealth mode by the first few. It becomes hard to price that in as you do not know exactly how much is controlled by one or a few entities, and you may well get this wrong.
I think that premine suffers from the similar stigma as "insider trading". It was pointed out to me by a Law Prof, that there was no such thing as insider trading, as no one knew the future with 100% and rather what gets called "insider trading" is rather quicker allocation of capital with attendant risk.
I feel that the degree of premine is simply another parameter in the variables for what constitutes a good coin, eg pay out rate, difficulty algo, upper limit of coins, speed etc.
tl;dr, confirmed premine lets you price that in. Defacto premines usually present anyway, and you can't price that in well.
jubalix -
Words matter - and despite your waffling ("defacto premine", "to some degree") your continued use of the word 'premine', applied to bitcoin, is disingenuous at best.
Ripple is totally premined. The alt-currencies you mention were premined.
Bitcoin was never premined: it was not anything even close.
Not even close. Plenty of people were aware of it, and plenty mined. It was the only cryptocurrency of which I'm aware that began its life in complete transparency, fully open to any and all; for those with eyes to see.
Your continued insistence in using the term 'premined' does both bitcoin and you a great disservice.