negatives
if it wasnt for altcoins, some premined scam coins would not exist, stealing real bitcoin value and leaving users holding a bag of s**t coins
I really think that this is the only one problem about altcoins at the moment. From my point of view alts are not so bad, they are giving something like more liquidity to the ecosystem
( well you know... at least few of them ), besides that, i dont see any problems related with alt coins.